An experimental study of the near wake of a two-dimensional hypersonic blunt body with mass addition

An experimental investigation of the steady, laminar near-wake flow field of a two-dimensional, adiabatic, c i rcular cylindcr with surface m a s s t r a n s f e r h a s been made a t a f r e e s t r e a m Mach number of 6. 0. t ra t ion f ie lds associated with the t r ans fe r of argon, nitrogen o r helium into the near wake were studied for m a s s t r ans fe r f rom the forward stagnation region, and f r o m the base. Fo r sufficiently low m a s s t r ans fe r r a t e s f r o m the base, fo r which a recirculating zone exists, the ent i re nea r -wake flow field co r re l a t e s with the momentum flux, not the m a s s flux, of the injectant, and the m a s s concentration field i s determined by counter-current diffusion into the r eve r sed flow. F o r m a s s addition from the forward stagnation region, the p r e s s u r e field i s undisturbed and the mass-concentration field i s nea r ly uniform in the regionof r eve r sed flow. The axial decay of argon m a s s concentration in the intermediate wake, downs t r e a m of the neck, i s explained with the aid of an integral solution in the incornpressihle plane, f r o m which the location of the virtual origin for the asymptotic far-wake solution has been dcrivcd as one resul t . The p r e s s u r e and mass -concenL i s t of Symbols M Mach numhcr