Research

Steady and Unsteady Numerical Heat Transfer and Fluid Flow with and without Radiation Effects, Numerical Techniques, Aerosols and Condensation Heat Transfer

Recent Work

Implicit Runge-Kutta Methods to Simulate Unsteady Incompressible Flows:

A numerical method (SIMPLE DIRK Method) for unsteady incompressible viscous flow simulation is presented. The proposed method can be used to achieve arbitrarily high order of accuracy in time-discretization which is otherwise limited to second order in majority of the currently used simulation techniques. A special class of implicit Runge-Kutta methods is used for time discretization in conjunction with finite volume based SIMPLE algorithm. The algorithm was tested by solving for velocity field in a lid-driven square cavity by the proposed method and a commercial computational fluid dynamics software program, FLUENT 6.2.16. Good agreement of the solutions of the proposed method with those of FLUENT and numerical solution of Ghia et al. establishes the feasibility of the proposed method.

For a sample animation of flow across a square cylinder, click on the following picture.

Porous Media:

Heat transfer in rectangular 2D and 3D channels with porous baffles is studied. Experiments were conducted to measure heat transfer enhancement in a 3-D channel with porous baffles. A finite volume code was developed to predict heat transfer flow in a 2-D channel with porous baffles. A commercially available software FLUENT was used to predict turbulent heat transfer in 3-D channel with porous baffles.

Mixed Convection Over a 3-D Backward Facing Step:

A finite volume code was developed to simulate mixed convection over a conducting horizontal backward facing step. Simulations were carried out for Re=200 and Ri (Richardson number) was varied from 0 to 3. The buoyancy effects on a flow over a backward facing step were found to move the edge of the recirculation zone further upstream. Numerical results may serve as benchmark for future work.

Heat Transfer over a Flat Tube Bundle:

Flat tubes are preferred to circular tubes in heat exchanger applications because: (a) larger heat transfer contact area and (b) less vibration due to smaller downstream recirculation bubble. A finite volume based code was developed to predict heat transfer over a flat tube bank. An algebraic technique was used to generate the body fitted grid and problem was solved in terms of contra-variant variables. The code validated by comparing results for flow over a series of circular cylinders confined in a parallel plate channel.