Showing papers by "Suhas V. Patankar published in 1988"

Calculation procedure for viscous incompressible flows in complex geometries

Abstract: A general calculation procedure for computing fluid flow and related phenomena in arbitrary-shaped domains is presented. The scheme has been developed for a generalized nonorthogonal coordinate system and is based on a control-volume approach with a staggered grid arrangement. The physical covariant velocity components are selected as the dependent variables in the momentum equations. The discretization equations for these velocity components are obtained by an algebraic manipulation of the discretization equations for the Cartesian velocity components. Such a practice avoids any reference to the differential form of the governing equations for the covariant velocity components. The coupling between the continuity and momentum equations is effected using the SIMPLER algorithm.

Combined forced and free laminar convection in the entrance region of an inclined isothermal tube

Abstract: An analysis is made of the combined forced and free convection for laminar flow in the entrance region of isothermal, inclined tubes. This involves the numerical calculation of the developing flow with significant buoyancy effects. Three independent parameters are introduced: the Prandtl number Pr, a modified Rayleigh number Ra*, and {Omega}, a parameter that measures the relative importance of free and forced convection. The inclination angle does not appear explicitly in the formulation. Numerical results are obtained for Pr = 0.7, 5, and 10, and representative values of Ra* and {Omega}. The axial development of the velocity profiles, temperature field, local pressure gradient, and the Nusselt number are presented. These results reveal that the buoyancy effects have a considerable influence on the fluid flow and heat transfer characteristics of the development flow. A comparison of the numerical results with the available experimental data is also presented.

Two-Equation Low-Reynolds-Number Turbulence Modeling of Transitional Boundary Layer Flows Characteristic of Gas Turbine Blades. Ph.D. Thesis. Final Contractor Report

Abstract: The use of low Reynolds number (LRN) forms of the k-epsilon turbulence model in predicting transitional boundary layer flow characteristic of gas turbine blades is developed. The research presented consists of: (1) an evaluation of two existing models; (2) the development of a modification to current LRN models; and (3) the extensive testing of the proposed model against experimental data. The prediction characteristics and capabilities of the Jones-Launder (1972) and Lam-Bremhorst (1981) LRN k-epsilon models are evaluated with respect to the prediction of transition on flat plates. Next, the mechanism by which the models simulate transition is considered and the need for additional constraints is discussed. Finally, the transition predictions of a new model are compared with a wide range of different experiments, including transitional flows with free-stream turbulence under conditions of flat plate constant velocity, flat plate constant acceleration, flat plate but strongly variable acceleration, and flow around turbine blade test cascades. In general, calculational procedure yields good agreement with most of the experiments.

Solution of some two-dimensional incompressible flow problems using a curvilinear coordinate system based calculation procedure

Abstract: The capabilities of a new curvilinear coordinate-based calculation procedure for incompressible flows are demonstrated by its application to a variety of test problems. The results are compared with the results of independent numerical and experimental studies available in the literature. These comparisons indicate that the proposed scheme can be successfully used to predict fluid flow and heat transfer phenomena in complex configurations.

Two-Equation Low-Reynolds-Number Turbulence Modeling of Transitional Boundary Layer Flows Characteristic of Gas Turbine Blades

Abstract: The use of low Reynolds number (LRN) forms of the k-epsilon turbulence model in predicting transitional boundary layer flow characteristic of gas turbine blades is developed The research presented consists of: (1) an evaluation of two existing models; (2) the development of a modification to current LRN models; and (3) the extensive testing of the proposed model against experimental data The prediction characteristics and capabilities of the Jones-Launder (1972) and Lam-Bremhorst (1981) LRN k-epsilon models are evaluated with respect to the prediction of transition on flat plates Next, the mechanism by which the models simulate transition is considered and the need for additional constraints is discussed Finally, the transition predictions of a new model are compared with a wide range of different experiments, including transitional flows with free-stream turbulence under conditions of flat plate constant velocity, flat plate constant acceleration, flat plate but strongly variable acceleration, and flow around turbine blade test cascades In general, calculational procedure yields good agreement with most of the experiments