An investigation into the effectiveness of passive control techniques on shock-induced boundary-layer separation at hypersonic s m s has been conducted. ' b o approaches to alleviating the turbulent S e w t i o n losses were examined: (1) Porous surface mass lransfer and (2) surface grooving. A total of four PerfOmted surfaces with varying porosities were evaluated. Three groove orientations with respect to the free-stream di-In addition to the experimental efforts to examine the shock-induced

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... oundary-layer separation, two-dimensional, thin-layer Navier-Stokes computations were undertaken. Results from the Navier-Stokes code compared favorably with the experimental data for the solid wall (i.e. reference) configuration. rection were also studied: transverse, swept, and longitudinal. Test results from these passive control techniques were compared to results from an "uncontrolled" shock impingement to determine the relative effectiveness of the devices. These comparisons indicated that the porous surface with the greatest porosity provided the largest reduction in the pressure rise across the oblique shock wave; however, the length of the interaction region was significantly extended. Each of the grooved configmtions examined increased the peak pressure value. In general, the grooved surfaces tested were found lo be an ineffective means of suppressing the losses across the shock system at hypersonic 4 W=a) speeds. under litk 17. US code. me US. Govmvncnt has B royaltyfree lieensc u) exercise all righrs under the copyright daimed hmin for Governmental pipes. AU h e r rig& are resewed by the copyright owner.