The effects of repetitive laser-pulse energy depositions (5.5 mJ/pulse) onto a shock wave-boundary layer interaction region over cylinder-flare model in a Mach 1.92 flow are experimentally investigated. Depending on the nose shape and the flare angle, the flow patterns are subdivided to two; separated flow in which a slip line and a strong separation shock wave originated in the nose-cylinder junction appears, and a non-separated flow in which a slip line is not observed and the re-attachment shock wave is much weaker. At flare angles around 30°, the separation can be suppressed by laser energy deposition even of down to 5 kHz. The Schlieren-visualized flow patterns are well correlated to the drag characteristics, in which a larger drag is obtained without separation. A possible scenario of the separation control is that the disturbance introduced by the baroclinic vortex ring induced the boundary layer transition so that it became robust against the adverse pressure gradient. Under marginal conditions, dual mode flow patterns, that is, a partial and full suppression modes are obtained under the same operation conditions.

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The blunt-body with conical spike model was suggested and demonstrated by experimentally and numerically. The results obtained from calculation was qualitatively agreed with measured results. The major purposes of this model are maintaining axisymmetric flow, achieving small baseline drag and keeping vortex residence time in shock layer. An experimenal visualization indicate that the axisymmetric flow was maintained by the effect of the conical spike. The measured and calculated results indicated the baseline drag become smaller by attaching conical spike than the cylinder model. The analyzed results obtained from calculation shows the vortex residence time in shock layer of attaching conical spike model have kept almost same time of the cylinder model under same repetition frequency of energy deposition. The drag and drag reduction performance shows that the tendency have less dependence of attaching conical spike but certain condition achieved better performance than cylinder model. The best performance achieved l cone =8.7mm, d cone /d cylinder =0.50 and f=60kHz.Nomenclature η = efficiency of energy deposition U = flow speed ΔD = drag reduction D = drag D 0 = baseline drag of cylinder model f = frequency E = deposited energy per pulse d cone = bottom radius of conical spike d cylinder = radius of cylinder part l cone = length of conical spike δ = shock stand-off distance s = distance of energy deposition area from model head of cylinder part Q = spatial distribution of deposited energy source λ = step function q 0 = total input power per unit mass x 0 = center position of deposited energy source r 0 = radius of deposited energy source t = elapsed time τ = deposited energy pulse duration η a = effectively-deposited energy ratio

A ring-force balance system for a supersonic wind tunnel with a small test section was developed. This force balance system can measure an applied force independently by measuring the strain on the ring part. A theoretical analysis of this system was conducted under three conditions: an infinitesimally thin ring-force balance, a ring-force balance with finite thickness, and a ring-force balance with a support arm. From the analytical results, the azimuthal location, where the strain is zero for certain force components, varied based on the balance characteristics, such as the thickness or diameter of the ring part. A ring-force balance, which is based on this analysis, was designed and fabricated. The calibrated results showed that the designed balance was able to measure the force components with high accuracy and minimal interaction.

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