Serge Wüthrich

Coupled Euler/boundary-layer method for nonequilibrium, chemically reacting hypersonic flows

Reference LIN-ARTICLE-2007-013View record in Web of Science Record created on 2007-06-22, modified on 2016-08-08

Hypersonic flow in chemical non-equilibrium: A comparison of thin-layer Navier-Stokes and coupled Euler/boundary layer computations

Abstract A comparison of the computed flowfields for viscous hypersonic flow in chemical non-equilibrium is presented. Two different approximations of the aerothermochemistry equations have been considered: the thin-layer Navier-Stokes equations and a second-order coupling of the Euler and boundary layer equations. To avoid discrepancies arising from the choice of the physical and chemical models, the test case considered has been defined in a precise manner. In addition, close attention is paid to the appropriate flowfield properties to be compared. The detailed agreement obtained in the computed solutions for hypersonic flow over a hyperboloid provides a verification of the accuracy of the numerical methods employed.

Non-equilibrium hypersonic flow simulations using the second-order boundary layer equations

Abstract A coupled Euler/boundary layer method to calculate hypersonic re-entry flows in chemical non-equilibrium is described. The flow is divided into two regions, with the second-order boundary layer equations being applied in the inner (viscous) region and the Euler equations in the outer (inviscid) region. It is shown that this allows a good matching of the calculated profiles at the interface between the two regions. The inclusion of second-order effects is shown not only to modify significantly the calculated boundary layer profiles, but also to have a large influence on the computed surface coefficients.

Comparison of thin layer Navier-Stokes and coupled Euler / boundary layer calculations of non-equilibrium hypersonic flows

A comparison of thin layer Navier-Stokes and coupled Euler/boundary layer methods is presented. For the Navier-Stokes method, the inviscid fluxes are discretized using a Total Variation Diminishing (TVD) scheme, while a second-order central difference scheme is applied to the viscous terms. A fully-implicit, fully-coupled time discretization is employed. The external bow shock is captured by the scheme. For the coupled Euler/boundary layer method, the boundary layer equations, correct to second order in Re−1/2, are applied in the inner (viscous) region and the Euler equations including displacement effects are solved for the outer (inviscid) region. The external inviscid bow shock is determined by a shock-fitting procedure. The results of calculations for flow over a hyperboloid at Mach = 25.5 show excellent agreement for the wall coefficients and the normal profiles using the two methods.

On the influence of the choice of transport and chemical models for non-equilibrium hypersonic flow simulations

Reference LIN-ARTICLE-2007-009View record in Web of Science Record created on 2007-06-22, modified on 2016-08-08