Zapryagaev V.I.   Kavun I.N.   Trubitsyna L.P.  

High total pressure layer characteristics near the reattachment zone of supersonic separated flow

Reporter: Kavun I.N.

The present work contains the investigation results of the supersonic three-dimensional laminar separation flow structure in the compression corner.
Main attention is devoted on the analysis of the flow structure near the reattachment zone. A feature of this structure is the presence of a layer with high total pressure, which is located above the boundary layer. The total pressure value in this layer reaches 0.95 from the total pressure value in the free stream. The reason for the formation of a high-pressure layer is due to the presence of a near wall flow zone in which the flow compression is carried out isentropically in a compression wave with low losses of total pressure. The external part of the reattached flow is compressed in the reattachment shock wave and has big losses of the total pressure. Near the wall, the total pressure losses are also high due to the gas viscosity effect. As a result, above the boundary layer, there is a thin layer with high total pressure.
The detailed analysis of the flow structure in the reattachment area varied by the ledge inclination angles within the range of φ = 20° – 50° with the step of 10°.  Experiments are carried out in the hypersonic wind tunnel T-326 ITAM SB RAS. The free stream Mach number is М∞ = 6 and 8. The Reynolds number calculated over the plate length is ReL = 6.3⋅105 and ReL = 3.0⋅105, respectively.  Analysis included the Schlieren visualization of the flow and measurement of the Pitot pressure distribution above the surface of the inclined step by the total pressure tube. Experimental results are added by the data of 3D numerical calculation. Analysis of the obtained total pressure profiles has confirmed the existence of the high total pressure layer for every considered configuration of compression corner models (at М∞ = 6). It is found that at М∞ = 8 this layer exists too (the test for the model with the ascent angle φ = 30°). 

The work is supported by the Russian Foundation for Basic Research, Grant No. 16-01-00314 а.


To reports list