Oblique shock

About: Oblique shock is a research topic. Over the lifetime, 6551 publications have been published within this topic receiving 119823 citations.

Shock-turbulence interaction and the generation of noise

Abstract: Interaction of convected field of turbulence with shock wave is analyzed to yield modified turbulence, entropy spottiness, and noise generated downstream of the shock Analysis is generalization of single-spectrum-wave treatment of NACA-TN-2864 Formulas for spectra and correlations are obtained Numerical calculations yield curves of rms velocity components, temperature, pressure, and noise in db against Mach number for m = 1 to infinity; both isotropic and strongly axisymmetric (lateral/longitudinal = 36/1) initial turbulence are treated In either case, turbulence of 01 percent longitudinal component generates about 120 dbs of noise

Control of edney IV interaction by pulsed laser energy deposition

Abstract: An experimental investigation was conducted to examine the effect of a pulsed Nd:YAG laser energy addition on the shock structures and surface pressure in a Mach 3.45 flow past a sphere. Two configurations were considered: 1) a sphere in a uniform freestream and 2) an Edney IV interaction generated by impingement of an oblique shock on the bow shock of the sphere

Restricted Shock Separation in Rocket Nozzles

Abstract: In overexpanded rocket nozzles the e ow separates from the nozzle wall at a certain pressure ratio of wall pressure to ambient pressure. Flow separation and its theoretical prediction have been the subject of several experimental and theoretical studies in the past decades. Two distinctive e ow separation phenomena, the freeshock and restricted-shock separation, were observed in experiments with nozzles. Both phenomena are discussed in detail, and the system of recompression shocks and expansion waves is described. For the free-shock case three different shock structures in theplume can occur, namely the regular shock ree ection, the Mach disk, or a cap-like shock pattern. Theappearanceofthesedifferentplumepatternsis discussed. Theseshock structuresareconserved for the full-e owing, but overexpanded, nozzle. Numerical results obtained for existing rocket nozzles, e.g., Space ShuttleMain EngineorVulcain, show a qualitativegood agreement with experimental photographs.Furthermore, an explanation for the appearance of restricted shock separation, which has been widely unknown up to now, is given, analyzing why and under what conditions it occurs. The type of nozzle contour strongly ine uences this form of e ow separation, and restricted shock separation also occursin full-scale, thrust-optimized rocket nozzles. Based on the results established for e ow separation, an outlook on the generation of side loads is given.

Structure of a plane shock layer

Abstract: The structure of a plane shock wave is discussed and the expected range of applicability of the Navier‐Stokes equations within the shock layer is outlined. The shock profiles are computed using the Bhatnagar‐Gross‐Krook model of the Boltzmann equation and a uniformly converging iteration scheme starting from the Navier‐Stokes solution. It is shown that the Navier‐Stokes solution remains a good approximation in the high‐pressure region of the shock layer up to approximately the point of maximum stress for all shock strengths. In the low‐pressure region, the correct profiles deviate with increasing shock strength from the Navier‐Stokes solution. The physical significance of the kinetic model used and the relation of the present study to previous theoretical and experimental work is discussed.

Shock waves in arbitrary fluids

Abstract: The following investigation tries to clear up the general hydrodynamical and thermodynamical foundations of the shock phenomenon.1 The first part, Sections 2–5, answers the question: What are the conditions for the equation of state of a fluid under which shocks with their distinctive qualitative features may be produced. These conditions, enumerated in Section 3, are partly of differential, partly of global nature. The second part, Sections 6–7, investigates the physical structure of the shock layer whose “infinitesimal” width is of the order of magnitude e provided heat conductivity and viscosity are small of the same order. Initial state and final state are singular points for the differential equations of the shock layer, and it is shown that they are of such a nature as to make one expect the problem to have a unique solution.