Hypersonic rarefied flow about a delta wing - direct simulation and comparison with experiment

Abstract

Three-dimensional simulations of hypersonic rarefied flow about a delta wing are performed using the direct simulation Monte Carlo method of Bird, and the results of the computations are compared with recent experimental data obtained in a vacuum wind tunnel at the DLR in Gottingen, Germany. The present study considers Mach 8.89 nitrogen flow for a range of conditions that include Knudsen numbers of 0.016-3.505 for an incidence angle of 30 deg, and angles of incidence of 15-60 deg for a constant Knudsen number of 0.389. The calculations provide details concerning the flowfield structure and surface quantities. Comparisons between the calculations and the available experimental measurements are made for aerodynamic and overall heat transfer coefficients and recovery temperature. The agreement between the measured and calculated data are very good, well within the estimated measurement uncertainty. Comparisons are also made with modified Newtonian and free-molecule theories.moment coefficient (with respect to the body apex) D = drag force d -diameter Kn = Knudsen number L = lift force / = reference length M = Mach number p = pressure q = heat transfer rate R = radius Re = Reynolds number T -temperature 7i nt = internal temperature TOY = overall temperature T r = recovery temperature T tT = translational temperature T w = wall temperature V = speed x,y,z = Cartesian coordinates a. = incidence angle of upper surface, positive leeward rj = distance along the stagnation streamline (measured from the body) p = density Presented as Paper 91-1315 at the AIAA

DSMC grid methodologies for computing low-density, hypersonic flows about reusable launch vehicles

“…2 However, for computational efficiency, one would also like to have the same number of molecules in each cell which is difficult to achieve simply through local cell refinement tetrahedral grid code. 9 The code has many of the same features as the general two-dimensional DSMC code known as G2 developed by Bird 14 and is referred to as the G3 code. The G3 code handles multiple species with chemical reactions and models collisions with the VHS and Larsen-Borgnakke models.…”

“…This version also treats each tetrahedron as an individual cell; however a version exists that allows the tetrahedra to be treated as subcells within an overall structured, body-fitted grid. 9 The code provides for an arbitrary unstructured tetrahedral grid to be used as input.…”

“…8 The body-fitted DSMC code has been adapted from an unstructured, tetrahedral grid code used by Celenligil and Moss. 9 The Cartesian grid DSMC code is a new code under development by one of the authors (GJL) that uses a structured-grid, variable resolution approach. The modifications to and unique features of these codes are described, and the overall methodology for applying these codes to complex geometries is discussed.…”

Configuration Optimization of Hypersonic Vehicles under Transitional Flow Conditions

“…Delta wing has often been studied in the literature because of its simple geometry [7,10,11]. However, the size of the wing is difference from case to case.…”