IXV post-flight reconstruction and analysis of the aerothermodynamic measurements along the rarefied portion of the reentry trajectory

Numerical simulation of rarefied supersonic flows using a fourth-order maximum-entropy moment method with interpolative closure

“…The densities are fixed to atmosphericlike conditions, ρ L0 = 4 kg/m 3 and ρ R0 = 1 kg/m 3 , while the initial bulk velocity is zero and the temperature is T L0 = T R0 = 480 K. We simulate argon gas, assuming a constant elastic cross-section σ = 5.463 × 10 −19 m 2 , and we model the effect of collisions through the BGK collision operator, as discussed in Eq. (1). The mean collision time, τ , is computed with the approximated formula, τ = (nσv th ) −1 , where n is the local number density.…”

“…The development of mathematical and numerical models for simulating rarefied supersonic flows is of relevance to a variety of aerospace problems. These include the study of the atmospheric entry of spacecrafts and meteors, [1][2][3] the design of air-breathing electric propulsion systems, 4 and low-density aerodynamic facilities. 5 The characteristic feature of such flows is a relatively slow collisional relaxation time, often slower or comparable to the advection time scales.…”