Accession Number : ADA119074

Title :   Navier-Stokes Solutions for an Axisymmetric Nozzle in a Supersonic External Stream.

Descriptive Note : Final rept. Jun 78-Apr 81,

Corporate Author : AIR FORCE WRIGHT AERONAUTICAL LABS WRIGHT-PATTERSON AFB OH

Personal Author(s) : Hasen,Gerald A

PDF Url : ADA119074

Report Date : Mar 1982

Pagination or Media Count : 138

Abstract : Numerical solutions of the Navier-Stokes equations are obtained for an axisymmetric nozzle in supersonic external stream (M infinity = 1.94, Mj = 3.0, Re infinity = 2.2 x 10 to the 6th power). Five jet pressure conditions ranging from a highly over-expanded case which exhibits a Mach disc shock formation to a slightly under-expanded case are examined and solved numerically. MacCormack's explicit method is applied as the numerical algorithm. An adaptive grid scheme is utilized in the nozzle wake to allow the fine mesh region of the computational grid to remain in areas containing relatively high flow gradients. Locally dependent eddy viscosity modelling is applied in the form of a Cebeci-Smith two-layer model in the boundary layer regions on the nozzle walls, and a form of the Prandtl mixing length model in the nozzle wake. A two-dimensional wedge flat plate validation case was computed using these models with excellent results. The computational solutions of the axisymmetric nozzle accurately reproduced the experimentally observed viscous effects on the nozzle base pressure and shock wave locations that are caused by the thick nozzle base annulus. Correct transition was achieved numerically from regularly reflected shock waves at the line of symmetry in the jet core to a Mach disc reflection at the appropriate nozzle static pressure ratio. (Author)

Descriptors :   *Nozzles, *Propulsion systems, *Navier Stokes equations, Axisymmetric, Supersonic flow, External, Shock waves, Base pressure, Static pressure, Viscosity, Fluid dynamics, Compressible flow, Computations, Prandtl number

Subject Categories : Numerical Mathematics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE