Stagnation Temperature Effect on the Supersonic Flow Around Pointed Airfoils with Application for Air

Abstract

The aim of this work is to develop a new numerical calculation program to determine the effect of the stagnation temperature on the calculation of the supersonic flow around a pointed airfoils using the equations for oblique shock wave and the Prandtl Meyer expansion, under the model at high temperature, calorically imperfect and thermally perfect gas, lower than the dissociation threshold of the molecules. The specific heat at constant pressure does not remain constant and varies with the temperature. The new model allows making corrections to the perfect gas model designed for low stagnation temperature, low Mach number, low incidence angle and low airfoil thickness. The stagnation temperature is an important parameter in our model. The airfoil should be pointed at the leading edge to allow an attached shock solution to be seen. The airfoil is discretized into several panels on the extrados and the intrados, placed one adjacent to the other. The distribution of the flow on the panel in question gives a compression or an expansion according to the deviation of the flow with respect to the old adjacent panel. The program determines all the aerodynamic characteristics of the flow and in particular the aerodynamic coefficients. The calculation accuracy depends on the number of panels considered on the airfoil. The application is made for high values of stagnation temperature, Mach number and airfoil thickness. A comparison between our high temperature model and the perfect gas model is presented, in order to determine an application limit of the latter. The application is for air.

Review of wave drag reduction techniques: Advances in active, passive, and hybrid flow control

“…The combined effect of high-pressure and skin friction drag cause a temperature rise; this high temperature may cause ablation of the surface material. 30 The bluntness remained deliberately in the manufacturing of the wing leading surface and will ultimately change the structure of shock wave. 31…”

“…The combined effect of high-pressure and skin friction drag cause a temperature rise; this high temperature may cause ablation of the surface material. 30 The bluntness remained deliberately in the manufacturing of the wing leading surface and will ultimately change the structure of shock wave. 31 Thus, the designers faced problems in shaping the airfoil to get maximum aerodynamic efficiency and less heating effects and the shaping for low radar cross-section (RCS).…”

Gas effect for oblique and conical shock waves at high temperature

“…If there is an increase in the inclination of the wall, then we will have a compression of the flow and this study will be used to determine the local parameters of the flow. If there is a decrease in the inclination of the wall compared to the upstream flow, we will have in this case an expansion and the parameters of the flow will be determined by the use of the Prandtl Meyer function at HT [22,32]. To see the interest of the gas, we added the aerodynamic fineness (χ=C y /C x ) for each gas.…”

“…CO 2 , H 2 O, NH 3 and CH 4 are bad choices. To make a comparison, we added the results for air which are presented in [32].…”