Simulation of blunt leading edge aerothermodynamics in rarefied hypersonic flow

Abstract

The steady-state aerodynamic characteristics of a new family of blunted leading edges immersed in a high-speed rarefied air flow are examined by using a Direct Simulation Monte Carlo (DSMC) Method. A very detailed description of the flow properties has been presented separately at the vicinity of the nose and adjacent to the afterbody surface of the leading edges by a numerical method that properly accounts for non-equilibrium effects that arise near the leading edges and that are especially important at high Mach number. Comparisons based on geometry are made between these new blunt configurations and round leading edge. Some significant differences between these leading edges are noted on the flowfield structure and on the aerodynamic surface quantities. It is found that the upstream effects have different influence on velocity, density, pressure and temperature along the stagnation streamline ahead of the leading edges. The analysis also shows that, despite the seeming advantages of the new blunt leading edge shapes, round leading edge still provides smaller stagnation point heating. Nevertheless, round leading edge provides larger total drag than the new blunt shapes under the range of condition investigated

Non-linear radiation effect on dusty fluid flow near a rotating blunt-nosed body

“…Blunt-nosed bodies also help in alleviating the aerodynamic heating problem because heat flux for such shapes is far lower than that for sharply pointed bodies. 1,2 Suwono 3 was the one who initially used rotating round-nosed bodies for analyzing the effect of buoyancy forces on boundary-layer flow. The author solved the problem for the case of rotating hemispheres by using Görtler series expansion method for a wide range of Prandtl numbers (0.72<Pr<100).…”

Computational simulations of near-continuum gas flow using Navier-Stokes-Fourier equations with slip and jump conditions based on the modal discontinuous Galerkin method

“…When axis-symmetric blunt-bodies accelerate into supersonic or hypersonic speeds, they generate frontal bow shock with separated flows in the rear of the body, which results in a high drag. Moreover, the use of blunt shapes tends to reduce aerodynamic heating in the stagnation region compared with streamlined bodies [3][4][5].…”

“…Such regimes are characterized with a high degree of rarefaction, commonly called the Knudsen number. Previous studies have shown that the conventional Navier-Stokes-Fourier (NSF) equations without slip and jump boundary conditions cannot handle rarefied regimes [4,10,13,14]. Moreover, inaccurate predictions for the heat transfer on the frontal surface of re-entry vehicles were shown to significantly affect designs for thermal protection systems, which adversely impacts the aerodynamic forces acting on re-entry vehicles [2,15].…”