Hypersonic Flow over Closed and Open Nose Missile Bodies: Raw and SVD-Enhanced Schlieren Imaging, Numerical Modeling, and Physical Analysis

Abstract

Understanding and mitigating against high heat loads at leading and blunt aerodynamic surfaces during hypersonic flight represents an ongoing technological challenge. Recent work has shown that the commercial software package, STAR CCM+, can provide reliable predictions of hypersonic aerothermodynamic flow and heating, under a wide range of complex, but common conditions. This chapter presents a preliminary experimental and numerical investigation of hypersonic flow over closed- and open-nose missile bodies, where the latter have been proposed as a means of reducing leading edge heat transfer. Four contributions are presented. First, a novel singular value decomposition (SVD)-based image processing technique is introduced, which significantly enhances the quality of raw schlieren images obtained in high-speed compressible flows. Second, numerically predicted hypersonic flow about a scale-model missile body, obtained using STAR-CCM+, is validated against experimental schlieren image data, an empirical correlation connecting bow shock stand-off distance and shock density ratio, and estimated drag forces. Third, scaling and physical arguments are presented as a means of choosing appropriate gas equations of state and for interpreting results of numerical simulations and experiments. Last, numerical experiments show that the forward facing cavity used in our wind tunnel experiments functions as a heat sink, reducing heat fluxes on the missile body downstream of the cavity.