AXISYMMETRIC AND PLANAR FREE JETS FOR HYPERSONIC LOW DENSITY TEST FACILITIES.
Technical rept. no. 3, 1 Apr 64-15 Nov 65.
OHIO STATE UNIV COLUMBUS AERONAUTICAL AND ASTRONAUTICAL RESEARCH LABS
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The use of axisymmetric and planar free jets to generate hypersonic, low density flow was investigated, and design criteria for producing these flows established. Method of characteristics solutions defining the stream gradients for these flows were verified by pitot pressure surveys and an analytic prediction of Mach disc location was verified by schlieren photography. The experiments indicate that the undesirable high stream gradients of the sonic exit, axisymmetric free jets may be reduced by using short conical extensions to produce jets expanded from Mach numbers greater than unity. A free jet formed by an M 2 orifice showed both a decrease in stream gradients and an increase in test area caused by an aft movement of the Mach disc. An adverse influence of the Mach disc on a sphere model pressure distribution and shock shape was found when the model, of the same diameter as the orifice, was less than eight diameters upstream of the disc. The planar flows generated by shots showed a substantial reduction in stream gradients when compared with the axisymmetric jets. Full development of the planar flow was not achieved, even with slots of length to height ratio of 200, because of a strong shock system emanating from the ends of the slot. These oblique shocks terminated the isentropic expansion. Author
- Test Facilities, Equipment and Methods
- Fluid Mechanics