Engineering topics

Thareja, R. R.

Publications and source records attributed to Thareja, R. R..

3 records

NASA NTRS1991

Adaptive unstructured mesh methods for steady viscous flow

The solution of the equations governing steady laminar viscous flows on unstructured triangular meshes is addressed. The shortcomings of the standard adaptivity approaches for this class of problems are highlighted and a modified method based upon the combined use of mesh enrichment, mesh movement, and adaptive remeshing, is proposed. The behavior of the proposed scheme is demonstrated by applying it in the solution of compression corner flows.

Hassan, O.↗

NASA NTRS1990

Applications of an adaptive unstructured solution algorithm to the analysis of high speed flows

An upwind cell-centered scheme for the solution of steady laminar viscous high-speed flows is implemented on unstructured two-dimensional meshes. The first-order implementation employs Roe's (1981) approximate Riemann solver, and a higher-order extension is produced by using linear reconstruction with limiting. The procedure is applied to the solution of inviscid subsonic flow over an airfoil, inviscid supersonic flow past a cylinder, and viscous hypersonic flow past a double ellipse. A detailed study is then made of a hypersonic laminar viscous flow on a 24-deg compression corner. It is shown that good agreement is achieved with previous predictions using finite-difference and finite-volume schemes. However, these predictions do not agree with experimental observations. With refinement of the structured grid at the leading edge, good agreement with experimental observations for the distributions of wall pressure, heating rate and skin friction is obtained.

Thareja, R. R.↗

NASA NTRS1987

An adaptive finite element scheme for the Euler and Navier-Stokes equations

The implementation of two explicit finite element schemes for the solution of the compressible Euler and Navier-Stokes equations is presented. The schemes can be employed with general unstructured triangular meshes in two dimensions. Either scheme can therefore be used as the basic solver in a solution adaptive mesh procedure in a direct manner. The particular adaptive approach which is advocated here is intended for the solution of steady state problems only and involves an adaptive regeneration of the grid at prescribed stages during the false transient. The grid regeneration is accomplished by a mesh generator which has the capability of generating triangular grids over computational domains of arbitrary shape. The procedure is illustrated by solving transonic flows over multi-airfoil configurations and high speed flows, involving shock interactions, past circular cylinders.

Morgan, K.↗