
Accession Number : ADA182459
Title : LargeEddy Numerical Simulation of an Array of ThreeDimensional Impinging Jets.
Descriptive Note : Final rept. May 85Jul 86,
Corporate Author : FLOW RESEARCH CO KENT WA
Personal Author(s) : Rizk,M H ; Menon,S
PDF Url : ADA182459
Report Date : Apr 1987
Pagination or Media Count : 189
Abstract : Numerical simulations of a row of impinging jets are performed. Both the impinging jets and the fountains caused by the collision of the wall jets are modeled in the simulations. The problem considered contains the essential features of twin jets impinging on the ground, simulating the hovering configuration of a VTOL aircraft. The flow is assumed to be governed by the timedependent, incompressible NavierStokes equations. The largeeddy simulation approach is followed in which all scales resolvable by the grid resolution are computed explicitly, while the smallscale turbulence structures, which are nearly universal in character, are modeled by an eddy viscosity formulation that simulates the energy cascade into the small scales. The NavierStokes equations are solved using a staggered computational mesh. Central finite differencing is used to discretize all terms except the convective terms, which are discretized using the QUICK scheme. The AdamsBashforth scheme is used to advance the solution in time. The pressure Poisson equation is used in place of the continuity equation. Efficient direct solutions are obtained for the pressure field, which allows the continuity equation to be satisfied at each time step. This study focuses on the motion and dynamics of largescale structures that have been experimentally observed in jet flows. The behavior of the jets and the fountain due to introducing axisymmetric, azimuthal and random disturbances at the jet exists is investigated.
Descriptors : *IMPINGEMENT, *JET FLOW, *SIMULATION, *NUMERICAL METHODS AND PROCEDURES, EFFICIENCY, EQUATIONS, FORMULATIONS, GRIDS, INCOMPRESSIBILITY, MESH, NAVIER STOKES EQUATIONS, NUMERICAL ANALYSIS, POISSON EQUATION, PRESSURE, RESOLUTION, SOLUTIONS(GENERAL), THREE DIMENSIONAL FLOW, VERTICAL TAKEOFF AIRCRAFT, VISCOSITY, COMPUTATIONS, CONTINUITY, CONVECTION, DYNAMICS
Subject Categories : Aerodynamics
Fluid Mechanics
Distribution Statement : APPROVED FOR PUBLIC RELEASE