Composite Reduced Navier Stokes Procedures for Flow Problems with Strong Pressure Interactions
Abstract
The Reduced Navier Stokes (RNS) formulation for viscous-inviscid interacting flows with significant upstream or 'elliptic' effects has been applied for transient flow over airfoils at incidence, and steady two and three dimensional flows over cavity, wing and afterbody configurations. The solution technique applies uniformly over the entire Mach number range and allows for shock-boundary layer interaction, and for moderate regions of axial and secondary flow recirculation. For two dimensional problems with recirculation, it has been demonstrated that for laminar flows there exists a critical Reynolds number, that is geometry dependent, above which the solution exhibits a breakdown. This occurs in the region of recirculation and very close to the reattachment point. This phenomena is grid dependent and can be missed with insufficiently refined grids or when artificial viscosity is introduced. It has been shown that the pressure-split RNS procedure is in fact a special form of flux-vector splitting that has very favorable properties for sharp shock capturing. A sparse matrix direct solver procedure has been applied for both two dimensional transient flows, and for three dimensional steady flows with the RNS flux-split strategy. A uni-directional or semi-coarsening multigrid procedure has been further developed for viscous interacting flows, where significant grid stretching is required in order to adequately evaluate both thin viscous layers and large inviscid regions, with and without shock interaction. (jg)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 30, 1990
- Accession Number
- ADA219621
Entities
People
- P. K. Khosla
- S. G. Rubin
Organizations
- University of Cincinnati