Annual Review of
Fluid Mechanics 2008

    Previous successful projects covered diverse topics of engineering as well as of fundamental importance. The outcome of these projects has appeared in seminal Journals and major conferences. 
    The research work involves modelling the flow of multiphase mixtures - either solid-particle-laden-gases or  vapour-droplet mixtures, e.g. moist air, - through a combination of numerical calculations (Computational Fluid Dynamics) and theoretical analysis. This is an interdisciplinary research area requiring synthesis of ideas from several fields such as fluid mechanics, thermodynamics, and, heat and mass transfer. Currently experiments are being conducted on condensation in microchannels and direct contact condensation.

The equations are valid for laminar to turbulent flow, and, for wide range of particle size (nanoparticles to large millimeter-sized particles). The theory includes the effects of inertia, Brownian diffusion, thermophoresis, turbophoresis, electrical and other body forces, gravity, shear-induced lift, surface roughness, and corrections due to Knudsen effect or finite slip Reynolds number. These equations reduce to the well known relations in the appropriate limits. Thus, for example, Fick's law of diffusion or the currently popular equations for the motion of nanoparticles can be viewed as subsets of the unified advection-diffusion theory derived. Experiments show that the deposition velocity varies differently with the size of particle in different ranges of particle size and it can vary by several orders of magnitude as particle size is altered. In the past, separate theories were needed in different particle size ranges and it would have been difficult to apply the theories to flow situations that are different from the situations for which the parameters of the theories were tuned. The unified advection-diffusion theory thus settles the quest over previous fifty years in the field for a physics-based explanation for the observed complex behaviour of particle transport.     J. Aerosol Science        Annual Review of Fluid Mechanics

The essence of the theory is that large-scale static temperature fluctuations caused by the segmentation of blade-wakes by successive blade-rows have a dominating influence on nucleation and droplet growth in turbines.  "True" turbulent fluctuations (due to shear-layer unsteadiness, etc.) are probably less important and are ignored.  A Lagrangian frame of reference is adopted and attention is focussed on a large number of individual fluid particles during their passage through the turbine.  Homogeneous nucleation and growth of droplets in each fluid particle is assumed to be governed by classical theories.  All fluid particles are assumed to experience the same pressure variation but those particles passing close to the blade surfaces suffer greater entropy production and therefore have higher static temperatures than those which pursue near-isentropic paths through the central portions of the blade passages.  Particles which suffer high loss therefore nucleate later in the turbine than those which experience little dissipation.  Condensation is thus viewed as an essentially random and unsteady phenomenon as the dissipation experienced by a fluid particle in one blade-row is assumed to be uncorrelated with its previous history.  On a time-averaged basis, the condensation zone is spread over a much greater distance in the flow direction than a simple steady-flow analysis would indicate and may encompass several blade-rows depending on the number of stages in the machine.  Predicted droplet size spectra show broad, highly-skewed distributions with large mean diameters and sometimes slight bimodality.  These are all characteristics of experimentally measured spectra in real turbines.  Conventional, steady-flow calculation methods, which predict a fixed Wilson point in a specific blade-row and a near-monodispersed droplet population, cannot reproduce any of these characteristics.

Philosophical Transactions of the Royal Society

The structures of stationary and moving fully and partly dispersed shock waves in vapour-droplet, two-phase flow are studied. The relaxation processes corresponding to the interphase transfer of mass, momentum and energy are analyzed. Pure substances only are considered, but, unlike most previous work, the droplet population is allowed to be polydispersed. It is shown how the effects of thermal relaxation for such a mixture can be elegantly incorporated into the analysis.
    Three types of fully dispersed wave are identified. Type I waves are dominated by thermal relaxation and an approximate analytical solution is presented which gives results in close agreement with  accurate numerical solutions of the governing equations. The analysis predicts some unexpected behaviour of the thermodynamic variables and demonstrates the correct scaling parameters for such flows. An approximate analysis is also presented for Type II waves, dominated by both velocity and thermal relaxation. Type III waves, where all three relaxation processes are important, are of little practical significance and are only briefly discussed. Partly dispersed waves are also considered and the results of a numerical simulation of the relaxation zone are presented. A linearised solution of this problem is possible but, unlike other relaxing gas flows, does not give good agreement with the more exact numerical calculations.
    The apparent discontinuity in the speed of sound in a vapour-droplet mixture as the wetness fraction tends to zero has been responsible for some confusion in the literature. This problem is resolved and it is shown that the transition from the two-phase equilibrium to the single-phase frozen speed of sound is continuous.
    Rankine-Hugoniot relations for wet vapour giving jump conditions across shock waves have been derived. Different types of transition have been identified (JFM1992, PhysFluids1994). Mechanisms of entropy production inside a shock wave in wet vapour have been discussed. The unsteady processes through which a partly-dispersed shock wave or a fully-dispersed wave attains its stable, steady structure have been computed.
   
CFD solutions include:
Analytical theories include:
JFM 1991    JFM1992    PhysicsFluids1992    PhysicsFluids1994    IUTAM1990    ISTP-IV-1991    

An unsteady time-marching technique has been developed that can be employed for any type of wet steam flow: nucleating or non-nucleating, subcritical or supercritical, steady or unsteady. It is robust, accurate, simple and fast. The scheme uses a novel technique that performs the integration of the droplet growth equations along the fluid path lines rather than the more usual method which involves freezing the gas dynamic flowfield instantaneously in order to perform the integration. This allows simultaneous solution of all the relevant equations and thus the correct coupling between the vapour-phase gasdynamics and the relaxation effects due to the droplets is maintained. The scheme maintains a polydispersed droplet spectrum which is essential for modelling the nucleation zone accurately. Calculations based on the present scheme show good agreement with experimental measurements, steady and unsteady, reported in the literature.     It is also shown how the unsteady condensation process due to supercritical heat addition may give rise to a polydispersed droplet spectrum. This has a direct bearing on a possible explanation of the poly-dispersity measured in steam turbines: a polydispersity which cannot be predicted with existing steady flow calculation methods. Time-marching prediction of unsteady condensation phenomena due to supercritical heat addition,  In Turbomachinery  : Latest Developments in a Changing Scene,  London, IMechE, 1991, p. 167-177. (ISBN 0852987617)

A unified theory on the interpretation of total pressure and total temperature in multiphase flows has been developed. The present approach applies to both vapour-droplet mixtures and solid particle laden gases, and at subsonic as well as supersonic velocities. It is shown here that the non-equilibrium processes occurring in the vicinity of a stagnation point are important. These processes may be responsible for the generation of entropy and affect the pressure and temperature at the stagnation point. They should be properly considered while inferring, say, flow velocity or entropy generation from Pitot measurements. By proper non-dimensionalization of the relevant parameters, it is possible to find a single (theoretically obtained) calibration curve for the total pressure as a function of the particle size, which is almost independent of the constituents of the multiphase mixture and of the flow conditions. The calibration curve is a plot of a pressure recovery factor versus Stokes number and specifies the total pressure under different nonequilibrium conditions. The total pressure, predicted by the present theory, varies monotonically between the two limiting values : the frozen total pressure (when there is no interphase mass, momentum and energy transfer in the decelerating flow towards the stagnation point) and the equilibrium total pressure (when the dispersed phase, either the liquid droplets or the solid particles, is always at inertial and thermodynamic equilibrium with the continuous vapour phase). The equilibrium total pressure is always higher than the frozen total pressure. It is shown that the equilibrium total temperature, on the other hand, may be higher or lower than the frozen total temperature. In addition, unlike the case of total pressure, the calibration curve for total temperature is not so universal, and the total temperature under nonequilibrium conditions is not necessarily bounded between the frozen and equilibrium values. It is further shown that the entropy of a multiphase mixture has to be carefully interpreted and is not unequivocally related to the total pressure even in steady, adiabatic flow.
    An explicit analytical theory as well as comprehensive numerical solutions of the governing equations are available.
Proceedings of Royal Society         ASME J Fluids Engineering

A theory of thermal choking due to non-equilibrium condensation in a nozzle is presented. An explicit equation for the critical quantity of heat in condensing flow has been derived. The equation is of general validity and applies to vapour-droplet flow with or without a carrier gas. It has been usually assumed in the literature that the classical gas dynamics result for the critical quantity of heat applies in condensing flow as well. The classical result is, however, obtained by considering external heat addition to an ideal gas in a constant area duct. In this paper it is shown that the area variation across the condensation zone (although small) and the depletion in the mass of vapour as a result of condensation have profound effects on the critical quantity of heat. The present equation (derived from an integral, control-volume approach) agrees very well with results from full time-marching solution of the non-equilibrium, differential gas dynamic equations. The classical gas dynamics result, on the other hand, seriously underpredicts the critical heat for condensing flow in nozzles (by a factor of three in the example calculation presented). ASME J Fluids Engineering

CFD of rotating fluid flow in a
Tesla disc turbine
(computed contours of tangential velocity,
radial velocity, pressure and pathlines)

Computation of fluid dynamics and performance of a microturbine
(First CFD simulation of a microturbine, a concept developed at MIT.)

CFD of interacting wall and offset
turbulent jets

Computation of indoor air quality
(The figure shows computed CO concentration inside a large kitchen in the campus)

Non-equilibrium Condensation
Self Adaptive Grid
(Click to enlarge)

Unsteady computation of wake segmentation in multistage turbine

Unsteady nonequilibrium condensation

  JFM 1991    IUTAM1990

Guha's Methodology: Computation of performance of a given gas turbine engine is well established. The research work of A Guha addresses the complementary question - how to design the best gas turbine engine for a specified task. A new systematic methodology for optimisation of civil turbofan engines has been developed. The work addresses the importance of non-perfect gas properties. Analytical formulae have been derived for determining optimum fan pressure ratio, optimum ratio of cold and hot jet velocities, optimum ratio of mean jet velocity and aircraft speed, etc. The work establishes new concepts such as the existence of true thermodynamic optimum values of the bypass ratio and the maximum temperature in the cycle. The work is interdisciplinary in nature, including economics. As an example, it is shown how to determine the optimum specific thrust (for a given mission) from a direct engine cost (DEC) analysis.
    In the new methodology, the optimum combination of overall parameters (FPR, OPR, TET, B) is determined concurrently that maximizes the overall efficiency while maintaining the specific thrust at a predetermined value established from a direct operating cost (DOC) analysis.  This is very different from the parametric studies (available in the literature) where the effects of the variation of a single variable are calculated numerically while all other variables are kept fixed - therefore at their non-optimum levels. The parametric studies are thus not capable of finding the true optimum combination.  Moreover, often such parametric studies may involve a large excursion in the value of the specific thrust which is unacceptable for a particular mission. So, even with the availability of a computational package, the present methodology offers a more logical approach.  Additionally, several, simple and explicit, new analytical relations have been derived here that accelerate the optimisation process and offer physical insight.  With these, the optimisation can be undertaken with hand calculations at the initial phase of a real design process and can also be treated realistically in a textbook.

IMechE Proc., Part A, J. Power and Energy, vol 223 (A4), 2009,
p451-465.  (15 pages)

Experiments and computations of indoor air quality
Building and Environment, vol 52, 2012, p.177-190.

Solar Energy

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INTERNATIONAL PUBLICATIONS of  A. Guha
(Academic Journals,   Edited Books, Refereed Conference,   Invited Lectures)
 

ACADEMIC JOURNALS 

	K Pradhan and A Guha, "A systematic study of blockage in three-dimensional branching networks with an application to model human bronchial tree", Theoretical and Computational Fluid Dynamics, vol 34, 2020, p. 301-332,  DOI: 10.1007/s00162-020-00523-1  (32 pages).
	K Pradhan , A Guha and PK Halder, "Characteristics of pressure drop, mass flow distribution and flow asymmetry in branching networks based on model human bronchial tree", ZAMM (Journal of Applied Mathematics and Mechanics), vol 100, 2020, Paper e201900022, p. 1-25,  DOI: 10.1002/zamm.201900022  (25 pages).
	A Guha, K Pradhan and A Jain, "Correction for semi-infinite assumption in the theories of natural convection and determination of average Nusselt number for finite inclined plates", Int. J. Thermal Sciences, vol 148, February Issue, 2020, Paper 106062, p.1-18  DOI: 10.1016/j.ijthermalsci.2019.106062  (18 pages).
	K Pradhan and A Guha, "Fluid dynamics of a bifurcation", Int. J. Heat and Fluid Flow, vol 80, December Issue, 2019, Paper 108483, p.1-29  DOI: 10.1016/j.ijheatfluidflow.2019.108483  (29 pages).
	K Pradhan and A Guha, "Fluid dynamics of oscillatory flow in three-dimensional branching networks", Physics of Fluids, vol 31(6), 2019, p.063601 - 1:29.  DOI: 10.1063/1.5093724  (29 pages). This Paper was highlighted by Physics of Fluids as "Editor's Pick".
	A Guha, A Jain and K Pradhan, "Computation and physical explanation of the thermo-fluid-dynamics of natural convection around heated inclined plates with inclination varying from horizontal to vertical", Int. J. Heat and Mass Transfer, vol 135, June 2019, p. 1130-1151. DOI: 10.1016/j.ijheatmasstransfer.2019.01.054 (22 pages).
	S Sengupta and A Guha, "Inflow-Rotor interaction in Tesla Disc Turbines: Effects of discrete inflows, finite disc thickness and radial clearance on the fluid dynamics and performance of the turbine", IMechE Proc., Part A, J. Power and Energy, vol 232(8), 2018, p. 971-991. DOI: 10.1177/0957650918764156 (21 pages).
PDF	A Guha and S Nayek, "The thermo-fluid-dynamics of natural convection around a heated a vertical plate with a critical assessment of the standard similarity theory", Physics of Fluids, vol 29(10), 2017, p.103607 - 1:17.  DOI: 10.1063/1.4990279 (17 pages).
PDF	S Sengupta and A Guha, "The fluid dynamics of symmetry and momentum transfer in microchannels within corotating discs with discrete multiple inflows", Physics of Fluids, vol 29(9), 2017, p.093604 - 1:13.  DOI: 10.1063/1.5001252  (13 pages).
PDF	A Guha and K Pradhan, "Secondary motion in three-dimensional branching networks", Physics of Fluids, vol 29(6), 2017, p.063602: 1-24.  DOI: 10.1063/1.4984919  (24 pages). This Paper was highlighted by Physics of Fluids as "Editor's Pick".
PDF	A Guha and S Sengupta, "A non-dimensional study of the flow through co-rotating discs and performance optimization of a Tesla disc turbine", IMechE Proc., Part A, J. Power and Energy, vol 231(8), 2017, p. 721-738. DOI: 10.1177/0957650917715148 (18 pages).
PDF	K Pradhan and A Guha, "CFD solutions for magnetohydrodynamic natural convection over horizontal and vertical surfaces", J. Molecular Liquids, vol 236, 2017, p. 465-476. DOI: 10.1016/j.molliq.2017.03.110 (12 pages).
PDF	A Guha and S Sengupta, "Non-linear interaction of buoyancy with von Kármán’s swirling flow in mixed convection above a heated rotating disc", Int. J. Heat and Mass Transfer, vol 108, May 2017, p. 402-416. DOI: 10.1016/j.ijheatmasstransfer.2016.11.082 (15 pages).
PDF	A Guha and K Pradhan, "A unified integral theory of laminar natural convection over surfaces at arbitrary inclination from horizontal to vertical", Int. J. Thermal Sciences, vol 111, 2017 January, p.475-490.  DOI: 10.1016/j.ijthermalsci.2016.08.011  (16 pages)
PDF	A Guha, K Pradhan and P Halder, "Finding order in complexity: A study of the fluid dynamics in a three-dimensional branching network", Physics of Fluids, vol 28(12), 2016, p.123602: 1-32.  DOI: 10.1063/1.4971315  (32 pages) This Paper was showcased by Physics of Fluids as "FEATURED ARTICLE". The COVER PAGE of the December 2016 Issue of Physics of Fluids is based on this Paper. This is the FIRST TIME the celebrated journal has changed its Cover Page since 1994.
PDF	A Guha and S Sengupta, "The physics of pressure variation in microchannels within corotating or static discs", Physics of Fluids, vol 28(10), 2016, p.103601 - 1:19.  DOI: 10.1063/1.4963370  (19 pages). This Paper was highlighted by Physics of Fluids as "Editor's Pick".
PDF	A Guha and S Sengupta, "Effects of finiteness on the thermo-fluid-dynamics of natural convection above horizontal plates", Physics of Fluids, vol 28(6), 2016, p. 063603 - 1:29 .  DOI: 10.1063/1.4953382  (29 pages).
PDF	A Guha and S Sengupta, "Analysis of von Kármán’s swirling flow on a rotating disc in Bingham fluids", Physics of Fluids, vol 28(1), 2016, p. 013601-1:30.  DOI: 10.1063/1.4937590  (30 pages).
PDF	S Sengupta and A Guha, "Flow of a nanofluid in the microspacing within co-rotating discs of a Tesla turbine", Applied Mathematical Modelling, vol 40, 2016, p. 485-499.  DOI: 10.1016/j.apm.2015.05.012  (15 pages).
	T Mondal, MK Das, and A Guha, "Periodic vortex shedding phenomenon for various separation distances between two plane turbulent parallel jets", Int. J. Heat and Mass Transfer, vol 99, 2016, p. 576-588,  DOI: 10.1016/j.ijheatmasstransfer.2016.03.095  (13 pages).
	T Mondal, A Guha and MK Das, "Effect of bottom wall proximity on the unsteady flow structures of a combined turbulent wall jet and offset jet flow", European Journal of Mechanics - B/Fluids, vol 57, 2016, p.101-114. DOI: 10.1016/j.euromechflu.2015.12.003  ( 14 pages).
	T Mondal, MK Das, and A Guha, "Transition of a steady to a periodically unsteady flow for various jet widths of a combined wall jet and offset jet", ASME J. Fluids Engineering, vol 138(7), 2016, 071206:1-11,  DOI: 10.1115/1.4032750  ( 11 pages).
	T Mondal, A Guha and MK Das, "Analysis of conjugate heat transfer for a combined turbulent wall jet and offset jet", ASME J. Heat Transfer, vol 138(5), 2016, p. 051701-1:13.  DOI: 10.1115/1.4032287  ( 13 pages).
	T Mondal, A Guha and MK Das, "Computational study of periodically unsteady interaction between a wall jet and an offset jet for various velocity ratios", Computers and Fluids, vol 123, 2015, p.146-161.  DOI: 10.1016/j.compfluid.2015.09.015  (16 pages).
	K Pradhan and A. Guha, "Natural convection above a horizontal plate in a nanofluid saturated porous medium with or without a magnetic field", J. Porous Media, vol 18 (6), 2015, p. 613-628. DOI: 10.1615/JPorMedia.v18.i6.50 (16 pages)
	AK Barik, SK Dash and A Guha, "Entrainment of air into an infrared supression (IRS) device using circular and non-circular multiple nozzles", Computers and Fluids, vol 114, 2015, p. 26-38. DOI: 10.1016/j.compfluid.2015.02.016 (13 pages).
	AK Barik, SK Dash and A Guha, "Experimental and numerical investigation of air entrainment into an infrared supression device", Applied Thermal Engg., vol 75, 22 January 2015, p. 33-44. DOI: 10.1016/j.applthermaleng.2014.05.042 (12 pages).
PDF	A Guha and S Sengupta, "The fluid dynamics of work transfer in the non-uniform viscous rotating flow within a Tesla disc turbomachine",  Physics of Fluids, vol 26 (3), 2014, 033601-1:27. DOI: 10.1063/1.4866263 (27 pages).
PDF	A Guha and S Samanta, "Effect of thermophoresis and its mathematical models on the transport and deposition of aerosol particles in natural convective flow on vertical and horizontal plates",  J. Aerosol Science, vol 77, 2014, p. 85-101. DOI: 10.1016/j.jaerosci.2014.06.005 (17 pages)
	K Pradhan, S Samanta and A Guha, "Natural convective boundary layer flow of nanofluids above an isothermal horizontal plate", ASME J. Heat Transfer, vol. 136, October 2014, 102501-1 : 102501-8. DOI: 10.1115/1.4027909 (8 pages).
	T Mondal, MK Das and A Guha, "Numerical  investigation of steady and periodically unsteady flow for various separation distances between a wall jet and an offset jet", J. Fluids and Structures, vol 50, 2014, p. 528-546. DOI: 10.1016/j.jfluidstructs.2014.07.009 (19 pages).
PDF	A Guha and S Sengupta, "Similitude and scaling laws for the rotating flow between concentric discs", IMechE Proc., Part A, J. Power and Energy, vol 228(4), 2014, p. 429-439. DOI: 10.1177/0957650914523947 (11 pages).
PDF	A Guha and K Pradhan, "Natural convection of non-Newtonian power-law fluids on a horizontal plate", Int. J. Heat and Mass Transfer, vol 70, March 2014, p. 930-938. DOI: 10.1016/j.ijheatmasstransfer.2013.11.001 (9 pages).
	AK Barik, SK Dash and A Guha, "New correlation for prediction of air entrainment into an infrared suppression  (IRS) device", Applied Ocean Research, vol 47, 2014, p. 303-312 . DOI: 110.1016/j.apor.2014.06.007 (10 pages)
	SK Dash and A Guha, "A theoretical study of the thermodynamics of gas expansion from a high pressure to a low pressure tank", Int. J. Mechanical Engineering Education, vol 42, no 2, April 2014, p.156-165. DOI: 10.7227/IJMEE.0009 (10 pages)
	S Samanta and A Guha, "Analysis of heat transfer and stability of magnetohydrodynamic natural convection above a horizontal plate with heat flux boundary condition",  Int. J. Heat and Mass Transfer, vol 70, March 2014, p. 793-802. DOI: 10.1016/j.ijheatmasstransfer.2013.10.049 (10 pages).
PDF	A Guha and S Samanta, "Effect of thermophoresis on the motion of aerosol particles in natural convective flow on horizontal plates", Int. J. Heat and Mass Transfer, vol 68, January 2014, p. 42-50. DOI: 10.1016/j.ijheatmasstransfer.2013.08.046 (9 pages).
PDF	N Chandrasekaran and A Guha, "Development and optimization of a sustainable turbofan aeroengine for improved performance and emissions", IMechE Proc., Part G, J. Aerospace Engineering, vol 227, November 2013, p. 1701-1719.  DOI: 10.1177/0954410012462183 (19 pages).
PDF	S Sengupta and A Guha, "Analytical and computational solutions for three-dimensional flow-field and relative pathlines for the rotating flow in a Tesla disc turbine", Computers and Fluids, vol 88, 2013, p.344-353.  DOI: 10.1016/j.compfluid.2013.09.008  (10 pages).
PDF	A Guha and S Samanta, "Closed-form analytical solutions for laminar natural convection on horizontal plates", ASME J. Heat Transfer, vol. 135, October 2013, 102501-1 : 102501-9. DOI: 10.1115/1.4024430 (9 pages).
	S Samanta and A Guha, "Magnetohydrodynamic free convection flow over a horizontal isothermal flat plate", Communications in Nonlinear Science and Numerical Simulation, vol 18, December 2013, p. 3407-3422,. DOI: 10.1016/j.cnsns.2013.04.023 (16 pages).
	S Samanta and A Guha, "A similarity theory for forced convection over horizontal plates", AIAA J. Thermophysics and Heat Transfer, vol 27, no. 3, July-September 2013, p. 506-514. DOI: 10.2514/1.T4033 (9 pages).
PDF	A Guha and S Sengupta, "The fluid dynamics of the rotating flow in a Tesla disc turbine", European Journal of Mechanics - B/Fluids, vol. 37 (January_February), 2013, p.112-123.  DOI:10.1016/j.euromechflu.2012.08.001 (12 pages). The Paper is 3rd most downloaded even 48 months after its publication!
PDF	A Guha, D Boylan and P Gallagher, "Determination of optimum specific thrust for civil aero gas turbine engines: a multidisciplinary design synthesis and optimisation", IMechE Proc., Part G, J. Aerospace Engineering, vol 227, Issue 3, March 2013, p. 502-527.  DOI: 10.1177/0954410011435623 (26 pages).
PDF	S Sengupta and A Guha, "A theory of Tesla disc turbines", IMechE Proc., Part A, J. Power and Energy, vol. 226(5), 2012, p.650–663.  DOI: 10.1177/0957650912446402 (14 pages).
PDF	S Samanta and A Guha, "A similarity theory for natural convection from a horizontal plate for prescribed heat flux or wall temperature", Int. J. Heat and Mass Transfer, vol 55, Issues 13-14, June 2012, p. 3857-3868.   DOI: 10.1016/j.ijheatmasstransfer.2012.02.031. (12 pages).
PDF	S Saha, A Guha, S Roy, "Experimental and computational investigation of indoor air quality inside several community kitchens in a large campus", Building and Environment, vol 52, 2012, p.177-190.   DOI: 10.1016/j.buildenv.2011.10.015 . (14 pages).
PDF	N Chandrasekaran and A Guha,  "Study of prediction methods for NOx emission from turbofan engines", AIAA J. Propulsion and Power, vol 28, no. 1, Jan-Feb 2012, p.170-180, DOI: 10.2514/1.B34245. (11 pages).
PDF	A Guha and B Smiley, "Experiment and analysis for an improved design of the inlet and nozzle in Tesla disc turbines ", IMechE Proc., Part A, J. Power and Energy, vol 224, no. A2, 2010, p.261-277.   DOI: 10.1243/09576509JPE818. (17 pages).
PDF	GP Hoya and A Guha, "Design of a test rig and study of the performance and efficiency of a Tesla disc turbine". IMechE Proc., Part A, J. Power and Energy, vol 223, no. A4, 2009, p.451-465.  DOI: 10.1243/09576509JPE664. (15 pages).
PDF	Single-authored, A Guha, "A generalized mass transfer law unifying various particle transport mechanisms",  Heat Mass Transfer, vol 44, 2008, p. 1289-1303. DOI:10.1007/s00231-008-0369-5 (15 pages).
PDF	Single-authored, A Guha, "Transport and deposition of particles in turbulent and laminar flow", Annual Review of Fluid Mechanics, vol. 40, 2008, p. 311-341. (31 pages). A paper in Annual Review of Fluid Mechanics is considered a top accolade in the field.
PDF	Y Mei & A Guha, "Modification of the upwind schemes for the computation of condensing two-phase flow", IMechE Proc., Part A, J. Power and Energy,  vol. 220, 2006, p. 809-814.
PDF	Y Mei & A Guha, "Implicit numerical simulation of transonic flow through turbine cascades on unstructured grids",  IMechE Proc., Part A, J. Power and Energy, vol 219, no A1, 2005, p. 35-47. (13 pages).
PDF	Single-authored, A Guha,  "Effects of internal combustion and non-perfect gas properties on the optimum performance of gas turbines",  IMechE Proc., Part C, J. Mechanical Engineering Science, vol 217, no A4, 2003, p. 1085-1099. (15 pages).
PDF	Single-authored, A Guha, "Optimisation of aero gas turbine engines",  The Aeronautical Journal, vol.105 , No. 1049 , July 2001, p. 345-358. https://doi.org/10.1017/S0001924000012264 (14 pages). The COVER PAGE of the July 2001 Issue of Aeronautical Journal is based on this Paper.
PDF	Single-authored, A Guha,  "Optimum fan pressure ratio for bypass engines with separate or mixed exhaust streams", AIAA J. Propulsion and Power, vol 17, no. 5, Sept-Oct 2001, p.1117-1122.
PDF	Single-authored, A Guha, "Performance and optimisation of gas turbines with real gas effects",  IMechE Proc., Part A, J. Power and Energy, vol 215, no A4, 2001, p. 507-512.
PDF	Single-authored, A Guha,  "An efficient generic method for calculating the properties of combustion products",  IMechE Proc., Part A, J. Power and Energy, vol. 215 , No. A3 , 2001, p. 375-387. (13 pages).
PDF	Erratum on “Determination of the optimum performance of gas turbines” by JH Horlock, IMechE Proc., Part C, J. Mechanical Engineering Science , vol. 215,  2001, p. 1378. (Errors found and communicated by A Guha.)
PDF	Single-authored, A Guha,  "Computation, analysis and theory of two-phase flows",  The Aeronautical Journal, vol. 102, No. 1012, 1998, p. 71-82. https://doi.org/10.1017/S0001924000065556  (12 pages).
PDF	Single-authored, A Guha,  "A simple, analytical theory for interpreting measured total pressure in multiphase flows",  ASME J. Fluids Engg., vol. 120, June  1998, p 385-389.
PDF	Single-authored, A Guha,  "A unified theory for the interpretation of total pressure and temperature in two-phase flows at subsonic and supersonic speeds", Proceedings of the Royal Society, vol. 454, 1998, p. 671-695. (25 pages).
PDF	J. Murray, A. Guha & A. Bond,   "Overview of the Development of Heat Exchangers for Use in Air-Breathing Propulsion Pre-Coolers",  Acta  Astronautica, vol. 41, no. 11, 1997, p. 723-729
PDF	Single-authored, A Guha,   "A unified Eulerian theory of turbulent deposition to smooth and rough surfaces",  J. Aerosol Science, vol. 28, no. 8, 1997, p. 1517-1537. (21 pages).
PDF	Single-authored, A Guha,   "Analysis and computation of non-equilibrium two-phase flow", Sadhana (J. Indian Academy of Sciences), vol. 22, part 3, June  1997, p 295-321. (27 pages).
PDF	Single-authored, A Guha,   "Thermal choking due to non-equilibrium condensation",  ASME Journal of Fluids Engineering, vol. 116, 1994, p 599-604.
PDF	A. Guha and S.K. Biswas,  "On Leonardo da Vinci’s cat and mouse problem",  Bulletin of Institute of Mathematics & Its Applications, Jan/Feb, vol. 30, 1994, p. 12-15.
PDF	A Guha and J.B. Young,  "The effect of flow unsteadiness on the homogeneous nucleation of water droplets in steam turbines",  Philosophical Transactions  A of  The Royal Society, vol. 349, 1994, p. 445-472.  (28 pages).
PDF	Single-authored, A Guha,   "A unified theory of aerodynamic and condensation shock waves in vapour-droplet flows with or without a carrier gas",  Physics of Fluids, vol 6, no 5, 1994, p 1893-1913. (21 pages).
PDF	Single-authored, A Guha,   "Jump conditions across normal shock waves in pure vapour-droplet flows",  Journal  of  Fluid Mechanics, vol 241,1992, p 349-369. (21 pages).
PDF	Single-authored, A Guha,  "Structure of partly dispersed normal shock waves in vapour-droplet flows", Physics of Fluids A, vol 4, no 7, 1992, p 1566-1578. (13 pages).
PDF	J.B. Young and A Guha,   "Normal shock wave structure in two-phase vapour-droplet flows", Journal of Fluid Mechanics, vol. 228, 1991, p 243-274. (32 pages).
PDF	J. Srinivasan and A Guha,   "Concentration profile in the gradient zone of small solar ponds", Solar Energy, vol. 38, no. 2, 1987, p 135-136.
PDF	J. Srinivasan and A Guha,  "The effect of bottom reflectivity on the performance of a solar pond",  Solar Energy, vol. 39, no. 4, 1987, p 361-367.

Springer 2007 ISBN: 3540358455

TataMcGrawHill2002 ISBN: 0070474435

VKI 1995 ISSN 0377-8312

ELSEVIER1992 ISBN 0444898514

IMechE 1991 ISBN 0852987617

Springer 1990 ISBN 3540502033

 

EDITED BOOKS

PDF	A Guha and  J.B. Young,   "Stationary and moving normal shock  waves in wet steam",  In Adiabatic Waves in Liquid-Vapour Systems, (ed. G.E.A. Meier and P.A. Thompson),  Springer Verlag, 1990, p 159-170. (ISBN 3540502033) (12 pages)
PDF	A Guha and  J.B. Young,   "Time-marching prediction of unsteady condensation phenomena due to supercritical heat addition",  In Turbomachinery  : Latest Developments in a Changing Scene,  London, IMechE, 1991, p. 167-177. (ISBN 0852987617)
Details	Single-authored, A Guha,  "The physics of relaxation processes and of stationary and non-stationary shock waves in vapour-droplet flows", In Transport Phenomena in Heat and Mass Transfer (ed. J.A. Reizes), Elsevier, 1992, p 1404-1417.  (ISBN 0444898514)   (14 pages)
	Single-authored, A Guha,   "Relaxation and shock wave structures in two-phase vapour-droplet  flows", Lectures in a short course on  Non-equilibrium Flow with Droplets and Bubbles  organized by the Czech Academy of Sciences, Prague, 3 - 8 April, 1993.
	Single-authored, A Guha,   "Non-equilibrium multiphase flow", Lectures in a short course on Metastable Behaviour of Fluids and Critical Phenomena organized by the Czech Academy of Sciences, Prague, October 30- November 2, 1994.
Details (110 pages)	Single-authored, A Guha,  "Two-phase Flows with Phase Transition", In  VKI Lecture Series 1995-06, von Karman Institute for Fluid Dynamics, Belgium, 1995, p 1-110.  (110 pages)
	Single-authored, A Guha, "Turbulent transport of particles and a generalized mass transfer law", pp. 29-38, In  Heat and Mass Transfer 2002, (Edited by SK Saha, SP Venkateshan, BVSSS Prasad and SS Sadhal), Tata-McGrawHill, New Delhi, p 1446, 2002. (ISBN: 0070474435)
Details (52 pages)	Single-authored, A Guha, “Shock waves in fluids with interphase transport of mass, momentum and energy (vapour-droplet mixtures and solid-particle-laden gases)”, Combined chapters, In Shock Waves Science and Technology Reference Library, Volume 1: Multiphase Flows, (Edited by MEH van Dongen), Springer, Berlin, 2007, pp. 135-186.     (ISBN: 3540358455)

 

CONFERENCE CONTRIBUTION (REFEREED)

Details	A Guha and J. B. Young,  "Time-marching prediction of unsteady condensation phenomena due to supercritical heat addition",  Proc. conf. on Turbomachinery  : Latest Developments in a Changing Scene,  London, IMechE, 1991,  p. 167-177. (11 pages.)
	A Guha and J.B. Young,   "Stationary and moving normal shock waves in wet steam", (12 pages) IUTAM Symposium on Adiabatic Waves in Liquid-Vapour Systems, Gottingen, 1989. INVITED Paper.
	Single-authored, A Guha, "The physics of relaxation processes and of stationary and non-stationary shock waves in vapour-droplet flows",  (14 pages)  Int. Symposium in Transport Phenomena (ISTP-IV), University of New South Wales, Sydney, 14-18 July, 1991.
	Single-authored, A Guha,  "Analysis and Computation of Non-equilibrium Two-phase Flow",  KEYNOTE Lecture at International Conference on Advances in Mechanical Engineering,  Golden Jubilee celebration of Mechanical Engineering Department of Indian Institute of Science, Bangalore, 20 - 22 December, 1995, Supplement, p 35 - 53. (19 pages)
	A Guha, J. Murray & A. Bond,  "Overview of the Development of Heat Exchangers for Use in Air-Breathing Propulsion Pre-Coolers", Paper  IAF-96-S.5.02,  47th International Astronautical Congress, Beijing, China, October 7-11, 1996.
Details	Single-authored, A Guha,  "On the formation of Droplet Spectra as Measured in Power-Plant Steam Turbines",  Proc. International Conference on Fluid Engineering,  JSME Centennial Grand Congress, Tokyo, 13 - 16  July, 1997, p 1395 - 1400.
	Single-authored, A Guha,  "Turbulent transport of particles and a generalized mass transfer law", KEYNOTE Lecture at  ASME/ISHMT International Conference on Heat and Mass Transfer, India, 3-5 January, 2002.
	M.J. Tierney, A. Guha,   A. Foster,  “Fast barriers – their use in civil defence and energy conservation”, World Renewable Energy Congress IX and Exhibition, Florence, Italy, 19-25 August 2006, Paper LEA107.

 

KEYNOTE LECTURES / INVITED SHORT COURSES

	Invited Paper at IUTAM Symposium on Adiabatic Waves in Liquid-Vapour Systems, Gottingen, 1989. Published as: A Guha and  J.B. Young,   "Stationary and moving normal shock  waves in wet steam",  In Adiabatic Waves in Liquid-Vapour Systems, (ed. G.E.A. Meier and P.A. Thompson),  Springer Verlag, 1990, p 159-170. (ISBN 3540502033)
	Short Course on  Non-equilibrium Flow with Droplets and Bubbles  organized by  The Czech Academy of Sciences, Prague, 3 - 8 April, 1993.
	Short Course on Metastable Behaviour of Fluids and Critical Phenomena organized by  The Czech Academy of Sciences, Prague, October 30 - November 2, 1994.
	VKI LECTURE SERIES 1995 - 06 on “Two-phase Flows with Phase Transition”,  von Karman Institute for Fluid Dynamics, Belgium, 29 May - 1 June, 1995.
	Keynote Lecture at International Conference on Advances in  Mechanical Engineering,  Golden Jubilee of Mechanical Engineering Department, Indian Institute of Science, Bangalore, 20 - 22 December, 1995. Re-published as:  A Guha,   "Analysis and computation of non-equilibrium two-phase flow", Sadhana (J. Indian Academy of Sciences), vol. 22, part 3, June  1997, p 295-321. (27 pages)
	Invited Lecture (2 hours) at  Toshiba Corporation, Yokohama, Japan, 17 July, 1997.
	Invited Lecture (2 hours) at Takasago Research & Development Center,  Mitsubishi Heavy Industries, Japan, 18 July, 1997.
	Keynote Lecture at the 5th bi-annual ASME/ISHMT International Conference on Heat and Mass Transfer (American Society of Mechanical Engg & Indian Society for Heat and Mass Transfer) 3-5 January, 2002. Published as:  A Guha, "Turbulent transport of particles and a generalized mass transfer law", pp. 29-38, In  Heat and Mass Transfer 2002, (Edited by SK Saha, SP Venkateshan, BVSSS Prasad and SS Sadhal), Tata-McGrawHill, New Delhi, p 1446, 2002. (ISBN: 0070474435)
	Invited to give a Keynote Lecture at the 15 th International Conference on Mechanical Engineering ISME2007, Iran, May 2007. This was a fully-paid invitation; Guha was the only Keynote Speaker invited from UK, there are 2 Keynote Speakers from the US and 1 from Canada. This is the biggest international conference in the middle-east, this year more than 1800 papers were submitted, 500 have been selected for presentation at ISME2007. Dr Guha could not attend in the end.   http://www.isme2007.ir
	Invited by the prestigious journal Annual Review of Fluid Mechanics from Palo Alto USA to write an article on Turbulent Deposition of Particles to be published in its Volume 40 (2008). Annual Review of Fluid Mechanics, which has an impact factor of 12.5 and cited half life of >10, typically invites about 15 people worldwide each year for its single annual volume that contains about 15 articles.
	One of the invited 25 delegates from all over India at the 3rd Indo-American Frontiers of Engineering Symposium, 2010 at Agra, organized by the Indo-US Forum (Similarly, 25 delegates were handpicked from the USA.).
	Delivered the Dr R.S. Pandey Distinguished Lecture 2017 at the Mechanical Engineering Department of IIT Kanpur on 2 April 2017.
	Presented numerous lectures /seminars at various places in the world.

Quick Access to a few Reprints for personal reading only.  Please CITE the articles if you benefit by reading them.

Interphase Transport Processes J. Fluid Mechanics 1991	Non-equilibrium Condensation Phil Trans Royal Society 1994	Total Pressure in Multiphase Flow Proc. Royal Society 1998	Shock Wave in Multiphase Flow J. Fluid Mechanics  1992	Unsteady Condensation Shock IMechE ISBN 0852987617  1991
Turbulent Transport and Deposition J Aerosol Science 1997	Rankine-Hugoniot for Multiphase Physics of Fluids 1994	Thermal Choking ASME J Fluids Engg 1994	Analytical Theory of Total Pressure ASME J Fluids Engg 1998	Turbulent Multiphase Flow Annual Review Fluid Mech  2008
Mixed Convection on Rotating Disc Int J Heat Mass Transfer 2017	Natural Convection on Inclined Plate Int J Thermal Sciences 2017	Natural Convection on Finite Plate Physics of Fluids 2016	Natural Convection on Vertical Plate Physics of Fluids 2017	Natural Convection non-Newtonian Fluid Int J Heat Mass Transfer 2014
Thermophoresis in Natural Convection J Aerosol Science 2014	MHD Natural Convection J Molecular Liquids 2017	Thermophoresis Natural Convection Int J Heat Mass Transfer 2014	Similarity Theory Natural Convection Int J Heat Mass Transfer 2012	Integral Theory Natural Convection ASME J Heat Transfer 2013
Fluid Dynamics Branched Network Physics of Fluids 2016	Secondary Flow 3D Branched Network Physics of Fluids 2017	Fluid Dynamics of Symmetry Physics of Fluids 2017	Fluid Dynamics of Rotating Flow Eur J Mechanics B Fluids 2013	von Karman Flow in Bingham Fluid Physics of Fluids 2016
Pressure Variation in Microchannel Physics of Fluids 2016	Work Transfer in Microchannel Physics of Fluids 2014	Nanofluid in Microchannel Applied Math Modelling 2015	A Theory of Tesla Turbine IMechE J Power Energy 2012	Pathline in Tesla Turbine Computers & Fluids 2013
Experiments on Tesla Turbine IMechE J Power Energy 2009	Nozzle Design for Tesla Turbine IMechE J Power Energy 2010	Scaling Laws for Tesla Turbine IMechE J Power Energy 2014	Optimization of Tesla Turbine IMechE J Power Energy 2017	Inflow-Rotor Interaction Tesla Turbine IMechE J Power Energy 2018
Optimization of Aero Engine Aeronautical J. 2001	Real Gas Effects in Gas Turbine IMechE J Power Energy 2001	Optimization of Turbofan Engine IMechE J Aerospace Eng 2013	NOx Prediction in Turbofan Engine AIAA J Propulsion Power 2012	Sustainable Turbofan Engine (H2) IMechE J Aerospace Eng 2013
Optimum Fan Pressure Turbofan AIAA J Propulsion Power 2001	Combustion Effects in Gas Turbine IMechE Mech Engg Sc 2003	Unsteady Analysis of Solar Pond Solar Energy 1987a	Concentration Profile in Solar Pond Solar Energy 1987b	Bio-inspired Heat Exchanger Acta Astronautica 1997
Transonic CFD of Turbine IMechE J Power Energy 2005	CFD Moving Shock Multiphase IUTAM ISBN 3540502033 1990	Theory, Computation Multiphase Aeronautical J. 1998	Generalized Mass Transfer Law Heat Mass Transfer 2008	Environment in Large Kitchens Building & Environment 2012

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