IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

An analysis is performed to study the influence of temperature-dependent viscosity and Prandtl number on the steady nonsimilar laminar forced convection flow over a rotating sphere up to the point of separation. The difficulties arising at the starting point of the streamwise coordinate and at the point of separation are overcome by applying the method of quasilinear implicit finite difference scheme with an appropriate selection of finer step size along the streamwise direction. The results indicate that the effect of variable viscosity and Prandtl number is to move the point of separation downstream, but the rotation parameter has the reverse effect. For higher wall temperature than the free stream temperature, beyond a certain critical value of the dissipation parameter, the cooler free stream is unable to cool the hot wall due to the "heat cushion" provided by the frictional heating. The heat transfer rate is found to depend strongly on viscous dissipation but the skin frictions are little affected by it. In general, the results pertaining to variable fluid properties differ significantly from those of constant fluid properties.

Department of Mathematics

Acta Mechanica

Steady nonsimilar axisymmetric water boundary layers with variable viscosity and Prandtl number

An analysis is performed to obtain the non-similar solution of a steady compressible laminar boundary layer flow over a yawed infinite circular cylinder with non-uniform slot injection (or suction) and non-uniform wall enthalpy. The difficulties arising at the starting point of the streamwise coordinate, at the edges of the slot and at the point of separation are overcome by applying the method of quasilinear implicit finite-difference scheme. It is observed that the separation can be delayed by non-uniform slot suction and also by moving the slot downstream but the effect of non-uniform slot injection is just the reverse. An increase in March number and total enthalpy at wall causes the separation to occur earlier while cooling delays it. The non-uniform total enthalpy at the wall (i.e., the cooling or heating of the wall in a slot) has very little effect on the skin friction and hence on the point of separation. © 2001 Elsevier Science Ltd. All rights reserved.

International Journal of Heat and Mass Transfer

Non-uniform mass transfer or wall enthalpy into a compressible flow over yawed cylinder

Nonsimilar solution of the unsteady laminar incompressible magneto-hydrodynamic boundary layer flow and heat transfer for an electrically conducting fluid over two-dimensional and axisymmetric bodies in the presence of an applied magnetic field has been obtained. The effects of surface mass transfer, Joule heating and viscous dissipation are included in the analysis. Numerical computation have been carried out for the flow over a circular cylinder and a sphere using an implicit finite difference scheme in combination with a quasi-linearization technique. It is observed that magnetic field and suction cause the location of vanishing skin friction to move downstream while, the effect of injection is just the opposite. The effect of magnetic field on the skin friction is more pronounced as compared to its effect on the heat transfer. On the other hand, the heat transfer is strongly affected by the viscous dissipation and the effect is more for large times. However, heat transfer responds comparatively less to the fluctuations of the free stream than the skin friction. © Springer-Verlag 2001.

Unsteady two-dimensional and axisymmetric MHD boundary-layer flows

An analysis is performed to study the effects of nonuniform multiple slot injection (suction) and nonuniform wall enthalpy on the steady nonsimilar compressible laminar boundary-layer flow over a two-dimensional and axisymmetric bodies. Nonsimilar solution is obtained from the origin of the streamwise coordinate to the exact point of separation. The difficulties arising out at the starting point of the streamwise coordinate, at the edges of the slots and at the point of separation are overcome by applying the method of quasilinear implicit finite difference scheme with an appropriate selection of finer step sizes along the streamwise direction. It is found that the nonuniform multiple slot injection moves the point of separation downstream but the nonuniform multiple slot suction has the reverse effect. Also, separation can be delayed more effectively by applying nonuniform multiple slot injection as compared to the nonuniform single slot injection. The nonuniform total enthalpy at the wall (i.e., the cooling or heating of the wall in the slots) along the streamwise coordinate has very little effect on the skin friction and thus on the point of separation.

Nonuniform multiple slot injection (suction) or wall enthalphy into a steady compressible laminar boundary layer

An analysis is performed to study the unsteady laminar incompressible boundary-layer flow of an electrically conducting fluid in a cone due to a point sink with an applied magnetic field. The unsteadiness in the flow is considered for two types of motion, viz. the motion arising due to the free stream velocity varying continuously with time and the transient motion occurring due to an impulsive change either in the strength of the point sink or in the wall temperature. The partial differential equations governing the flow have been solved numerically using an implicit finite-difference scheme in combination with the quasilinearization technique. The magnetic field increases the skin friction but reduces heat transfer. The heat transfer and temperature field are strongly influenced by the viscous dissipation and Prandtl number. The velocity field is more affected at the early stage of the transient motion, caused by an impulsive change in the strength of the point sink, as compared to the temperature field. When the transient motion is caused by a sudden change in the wall temperature, both skin friction and heat transfer take more time to reach a new steady state. The transient nature of the flow and heat transfer is active for a short time in the case of suction and for a long time in the case of injection. The viscous dissipation prolongs the transient behavior of the flow.

Unsteady MHD forced flow due to a point sink

The steady nonsimilar compressible laminar boundary-layer flow over a yawed infinite circular cylinder with nonuniform slot injection (suction) has been studied up to the point of separation. The finite discontinuities arising at the leading and trailing edges of the slot for the uniform slot injection (suction) are removed by choosing appropriate nonuniform mass transfer distributions in the slot. The difficulties arising at the starting point of the streamwise co-ordinate, at the edges of the slot and at the point of separation are overcome by applying the method of quasilinear implicit finite difference scheme with an appropriate selection of finer step size along the streamwise direction. It is found that the nonuniform slot injection moves the point of separation downstream but the nonuniform slot suction has the reverse effect. The increase of Mach number shifts the point of separation upstream due to the adverse pressure gradient. The increase of total enthalpy at the wall causes the separation to occur earlier while cooling delays it. The yaw angle has very little effect on the location of the point of separation.

Nonuniform slot injection (suction) into a compressible flow

Steady two-dimensional and axisymmetric compressible nonsimilar laminar boundary-layer flows with non-uniform slot injection (or suction) and non-uniform wall enthalpy have been studied from the starting point of the streamwise co-ordinate to the exact point of separation. The effect of different free stream Mach number has also been considered. The finite discontinuities arising at the leading and trailing edges of the slot for the uniform slot injection (suction) or wall enthalpy are removed by choosing appropriate non-uniform slot injection (suction) or wall enthalpy. The difficulties arising at the starting point of the streamwise co-ordinate, at the edges of the slot and at the point of separation are overcome by applying the method of quasilinear implicit finite difference scheme with an appropriate selection of finer step size along the streamwise direction. It is observed that the non-uniform slot injection moves the point of separation downstream but the non-uniform slot suction has the reverse effect. The increase of Mach number shifts the point of separation upstream due to the adverse pressure gradient. The increase of total enthalpy at the wall causes the separation to occur earlier while cooling delays it. The non-uniform total enthalpy at the wall (i.e., the cooling or heating of the wall in a slot) along the streamwise co-ordinate has very little effect on the skin friction and thus on the point of separation. © 1994 Springer-Verlag.

World University root node

Non-uniform slot injection (suction) or wall enthalpy into a steady nonsimilar compressible laminar boundary layer

A semi-similar solution of an unsteady hypersonic laminar compressible boundary layer flow over a slender axisymmetric body with massive blowing has been obtained when the free stream velocity varies arbitrarily with time. The governing partial differential equations have been solved numerically by combining the implicit finite difference scheme with the quasi-linearization technique. The results have been obtained for (i) an accelerating/decelerating stream and (ii) a fluctuating stream. The skin friction responds to the fluctuation in the free stream more compared to the heat transfer. It is observed that the effect of large injection (blowing) rates is to move the viscous boundary layer away from the surface. The effect of the variation of the density-viscosity product across the boundary layer is found to be negligible for large blowing rates. Massive blowing reduces significantly the values of skin friction and heat transfer but the effect of the transverse curvature parameter is just reverse. Location of the dividing streamline increases as injection rate increases, but decreases with the increase of the transverse curvature parameter. © 1992.

International Journal of Engineering Science

Unsteady hypersonic boundary layers for slender axisymmetric bodies with large injection rates

This paper deals with the laminar unsteady compressible boundary layer flow of an electrically conducting viscous fluid at the stagnation point of an axi-symmetric blunt-nosed body with vectored mass transfer, non-zero dissipation parameter m( = u2s/2Hc) and an applied magnetic field. The semi-similar solutions have been obtained numerically using an implicit finite difference scheme in combination with the quasi-linearization technique. The results have been obtained for (i) an accelerating/decelerating stream and (ii) a fluctuating stream. The skin-friction responds to the fluctuation in the free-stream more compared to the heat transfer. In presence of the magnetic field velocity overshoot occurs which gives rise to the point of inflexion in velocity profile and for small wall values of the total enthalpy, the point of inflexion arises in velocity and total enthalpy profiles which may cause instability in the flows but this can be avoided in certain circumstances. Skin friction can be reduced by applying vectored mass transfer more compared to the mass transfer applied normal to the surface. The results also show that the skin friction coefficient increases but Nusselt number decreases as the magnetic parameter M increases. © 1991.

Unsteady laminar compressible boundary layers with vectored mass transfer and an applied magnetic field

Manipur in India is endowed with rich biodiversity and abundant natural resources. Despite inaccessibility, marginality and heterogeneity, the state has made good progress in agriculture and allied sectors. About 80% of the state population depends on agriculture for livelihood. However, agriculture sector in Manipur is facing the consequences of climate change. Climate change is a reality and an increasing trend in temperature, precipitation and emission of greenhouse gases has been observed in Manipur. The state is also projected to experience more of extreme rainfall and reduction in crop yields. As subsistence level farming is coupled with prevalent shifting cultivation, the small and marginal farmers will be most affected due to climate change. Hence, there is an urgent need for devising climate proof plan and climate ready policy for climate compatible agricultural development in Manipur. Location-specific climate smart technology baskets need to be devised or introduced and should be demonstrated through participatory approach, for ensuring a climate resilient production system, and a climate resilient ecosystem. The interactions between the system’s adaptation strategies and the mitigation potential should also be given due importance in the action plan for combating climate change. This article deals with the present status of agriculture and allied sector and various technological and policy options for climate resilient agriculture in the hill and mountain ecosystems of Manipur.&nbsp;