
Accession Number : ADA297454
Title : The Dependence of the TimeAsymptotic Structure of 3D Vortex Breakdown on Boundary and Initial Conditions.
Descriptive Note : Doctoral thesis,
Corporate Author : AIR FORCE INST OF TECH WRIGHTPATTERSON AFB OH
Personal Author(s) : Tromp, Jeffrey C.
PDF Url : ADA297454
Report Date : JUL 1995
Pagination or Media Count : 251
Abstract : The threedimensional, compressible NavierStokes equations are solved numerically to simulate vortex breakdown in tubes. Time integration is performed with an implicit BeamWarming algorithm, which uses fourthorder compact operators to discretize spatial derivatives. Initial conditions are obtained by solving the steady, compressible, and axisymmetric form of the NavierStokes equations using Newton's method. Stability of the axisymmetric initial conditions is assessed through 3D time integration. Unique axisymmetric solutions at a Reynolds number of 250 lose stability to 3D disturbances at a critical value of vortex strength, resulting in 3D and timeperiodic flow. Axisymmetric solutions at a Reynolds number of 1000 contain regions of nonuniqueness. Within this region, 3D time integration reveals only unique solutions, with nonunique, axisymmetric initial conditions converging to a unique solution that is steady and axisymmetric. Past the primary limit point, which approximately identifies critical flow, the solutions bifurcate into 3D periodic flows.
Descriptors : *VORTICES, *COMPUTATIONAL FLUID DYNAMICS, *COMPRESSIBLE FLOW, *NAVIER STOKES EQUATIONS, MATHEMATICAL MODELS, ALGORITHMS, STABILITY, EQUATIONS OF MOTION, TIME DEPENDENCE, GRIDS, THESES, FLOW VISUALIZATION, SOLUTIONS(GENERAL), NUMERICAL INTEGRATION, SUPERCRITICAL FLOW, OPERATORS(MATHEMATICS), MACH NUMBER, FREE STREAM, BIFURCATION(MATHEMATICS), DELTA WINGS, REYNOLDS NUMBER, PERIODIC VARIATIONS, STEADY FLOW, STAGNATION POINT, COUETTE FLOW, THREE DIMENSIONAL FLOW, AXISYMMETRIC FLOW, BURSTING STRENGTH.
Subject Categories : Fluid Mechanics
Distribution Statement : APPROVED FOR PUBLIC RELEASE