An efficient computational procedure is presented for tw*dimensional and axisymmetric blunt body flow calculations. The procedure is based on an implicit upwind differencing method with automatic mesh adaption and solution control to improve its reliability and ease of use. Inefficiencies due to transient flow evolution are minimized by using surface fits for the initial flow field, and by using a graduated grid procedure. Surface pressures and heat transfer rates are presented for spherical and cylinderical blunt bodies at Mach 6 and 8, including a type IV shock/shock interaction. An unusual numerical phenomenon was encountered with the use of Roe's flux difference scheme in the region of the stagnation streamline in the bow shock; a satisfactory remedy is demonstrated. v Introdution Blunt body flows are of great significance in the design of hypersonic vehicles. As shown in Figure l bluntbody flows occur in at least two important areas of a hypersonic vehicle: the nosetip and the cowl lip of the inlet. The blunt body flows result in high aerodynamic heating and pressure loads on the vehicle. Also, the bow shock in front of the blunt body creates an entropy layer which has a significant effect on the flow for a considerable distance downstream. So, even when the pressure distribution or heat transfer in the blunt body region are not of great interest, the blunt body solution may be required to accurately calculate the remainder of the flow over a vehicle.Numerous computer codes have been developed for calculating hypersonic blunt body flows [1,2,3,4,5,6,7,8]. The intent of most of these efforts was to study a particular fluid dynamic phenomenon of interest. Their intent was not necessarily to develop a useful tool for engineers and designers which is generally applicable to a wide range of blunt body flow fields. There is a need for a code which can rapidly and reliably obtain viscous real-gas solutions to cylinderical and axisymmetric blunt body problems. -< 'SeNor Research Engineer and AIAA Member 'Senior Researdl Enginur and AIAA MemberThis paper describes a new computer program called BLT for calculating supersonic/hypersonic twodimensional and axisymmetric blunt body flows. BLT was developed primarily for providing starting solutions for the SPEAR/3D [9] space marching 3D-PNS code.BLT uses an improved implicit method which approximates a Newton method for the steady-state equations. The method is based on upwind differencing to provide stable solutions at high Mach numbers. The initial shock position and flow field are obtained from surface fits t o previously calculated solutions. The use of these good initial conditions and the use of graduated gridding allows the solution to converge rapidly.Calculated results are presented for a Mach 8 cylinderical blunt body with isothermal wall in an undisturbed freestream and also for a Type IV shock/shock interaction-similar to what might occur on the lip of a supersonic inlet cowl. The calculated surface pressures and heat transfer rates are compared t o experiment...

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