Effects of SWBLI and SWSWI in Mars Atmosphere Entry

The forthcoming manned exploration missions to Mars by means of complex geometry spacecrafts stimulate the study of aerodynamic, hypersonic phenomena such as Shock Wave-Boundary Layer Interaction (SWBLI) and Shock Wave-Shock Wave Interaction (SWSWI) also along the entry in Mars atmosphere. As already done by Zuppardi and co-workers in early papers where SWBLI and SWSWI were studied in Earth re-entry, also the present study has been carried out computationally by means of a DSMC code. The aim of the present paper is to quantify the effects of SWBLI and of SWSWI at the conditions of Mars entry and to compare these effects with those, already computed by the author at the conditions of Earth re-entry. Also in this paper, SWBLI has been studied considering an external, oblique shock wave impinging onto a flat plate on which gas was flowing and therefore a boundary layer was present. Computations have been carried out in the altitude interval 55-70 km. SWSWI has been studied considering the interaction of the shock wave on the leading edge of an airfoil (NACA-0010) with the shock wave stemming from the airfoil concave, lower surface at the hinge position in flapped configuration. Computer tests have been carried out at the altitude of 65 km, in the range of angles of attack 0-40 deg and considering three flap deflections: 0, 15, 30 deg. The quantification of the effects of both interactions has been carried out by means of the relative increase of local quantities such as the resultant of pressure, normal and tangential stresses and the heat flux. SWSWI has been quantified also in terms of global aerodynamic coefficients. The analysis verified that the SWBLI effects are higher in Earth re-entry. SWSWI is also higher in Earth re-entry in terms of global coefficients but the effects are higher in Mars entry in terms of the relative increase of local quantities.