Experimental Investigation Of Supersonic Flow Research Articles

Effect of porous material heating on the drag force of a cylinder with gas-permeable porous inserts in a supersonic flow

The paper presents the results of an experimental investigation of supersonic flow around a solid cylinder with a gas-permeable porous insert on its front end and of supersonic flow around a hollow cylinder with internal porous inserts in the presence of heating of the porous material. The experiments were performed in a supersonic wind tunnel with Mach number 4.85 and 7 with porous inserts of cellular-porous nickel. The results of measurements on the filtration stand of the air filtration rate through the cellular-porous nickel when it is heated are also shown. For a number of experiments, numerical modeling based on the skeletal model of a cellular-porous material was carried out.

Experimental investigation of supersonic flow over elliptic surface

AbstractThe coherent structures of flow over a compression elliptic surface are experimentally investigated in a supersonic low-noise wind tunnel at Mach Number 3 using nano-tracer planar laser scattering (NPLS) and particle image velocimetry (PIV) techniques. High spacial resolution images and the average velocity profiles of both laminar inflow and turbulent inflow over the testing model were captured. From statistically significant ensembles, spatial correlation analysis of both cases is performed to quantify the mean size and orientation of large structures. The results indicate that the mean structure is elliptical in shape and structure angles in separated region of laminar inflow are slightly smaller than that of turbulent inflow. Moreover, the structure angle of both cases increases with its distance away from from the wall. POD analysis of velocity and vorticity fields is performed for both cases. The energy portion of the first mode for the velocity data is much larger than that for the vorticity field. For vorticity decompositions, the contribution from the first mode for the laminar inflow is slightly larger than that for the turbulent inflow and the cumulative contributions for laminar inflow converges slightly faster than that for turbulent inflow

Experimental investigation of supersonic flow over a hemisphere

The experimental investigation of supersonic flow over a hemisphere was conducted using Nanoparticle-based Planar Laser Scattering (NPLS) technique in a supersonic quiet wind tunnel at Ma=2.68. Ahead of the hemisphere, boundary layer separation with the formation of a three-dimensional separated flow was observed, which was resulted from the interaction between the three-dimensional bow shock wave and the boundary layer. The complex flow structures of supersonic flow over the hemisphere were visualized. Based on the time correlation of NPLS images, time-space evolutionary characteristics of supersonic flow over the hemisphere were studied, and the evolutionary characteristics of the spanwise and streamwise large scale vortex structures were obtained, which have the features of periodicity and similar geometry.

Interaction of a transverse gas jet with supersonic flow in a dihedral

The results of an experimental investigation of supersonic flow at the Mach number M1=3 past a transverse gas jet flowing from an orifice in the edge of a dihedral with a linear angle of 90° are presented. The Mach number of the jet was varied from 1 to 3, and the ratio of the total pressure in the jet to the free stream pressure from 90 to 760. Visualization of the flow near the faces of the dihedral revealed the existence of internal lines of flow convergence and divergence in the region of three-dimensional separated flow, which indicates the presence of complex vortex structures. The dependence of the dimensions of the separated flow zone and the characteristic pressures in it on the jet parameters is explored.

Experimental investigation of supersonic flow about an obstacle with power delivery into the undisturbed flow

A technique and results of experimental investigation of supersonic flow about bodies with optical breakdown in the windstream are presented. Flow parameter evolution when pulsed power is delivered locally is tracked. Experimental and calculated flow patterns are compared.

Experimental investigation of supersonic flow over two cavities in tandem

A study is presented on supersonic flow over two rectangular cavities arranged in tandem at Mach 1.5, 2.5, and 3.5. Both time-mean and unsteady aspects of the flowfields are examined. For the purposes of this paper, cavities are chosen in which the oscillatory properties are due either to a fluid resonant phenomenon or to a fluid dynamic phenomenon. These are defined as type A and type B cavities, respectively. At Mach 1.5 and 2.5, the flow in a type A cavity is found to be completely altered by a preceding type B cavity. When the type B cavity is preceded by another type B cavity, only the level of the unsteady pressures and the high frequency modes of the oscillation are affected. When type A cavity precedes a type B cavity, only small quantitative changes are noted in the oscillatory behavior. The influence of the spacing between the two cavities is also addressed.

Computational and experimental investigation of cavity flowfields

This paper presents a computational and experimental investigation of supersonic flow past a cavity in a flat plate. The source of the particular interest in this problem is the ongoing study of the aerodynamic interference effects between a separating store and its bay in the parent body. An upwind relaxation scheme, utilizing flux vector splitting and line-Gauss-Seidel iterations, is used to solve Reynolds-averaged Navier-Stokes equations. Spatial discretizations of this two-dimensional analysis are based on implicit and finite-volume methods. Turbulence is modeled and shocks are captured. The flowfield of the symmetry plane at the half-width is computationally visualized and all flow properties are computed. Experimental tests are conducted in the Langley Unitary Plan Wind Tunnel to measure wall pressures and to capture schlieren photographs. Qualitative as well as quantitative data of computations and experiments agree very well. These two vehicles of investigation are merged to show open, closed and transitional cavity flow behaviors.

Interaction of a jet exhausting from a body with an opposing supersonic stream of rarefied gas

The experimental investigation of supersonic flow past a sphere with a jet exhausting from the front point of the sphere into the flow at large [1] and moderate [2] Reynolds numbers Re has revealed an effect of shielding from the oncoming stream, this leading to a decrease in the drag coefficient of the sphere and of the energy flux to it. A numerical simulation of the flow has been made in the case of supersonic flow past a sphere with a sonic jet from a nozzle situated on the symmetry axis in the continuum regime [3]. In the present paper, this problem is investigated for flow of a rarefied gas on the basis of numerical solution of a model kinetic equation for a monatomic gas.

Experimental investigation of flow over sharp cones with near-critical and supercritical vertex angle

This paper presents results of an experimental investigation of supersonic flow over sharp cones with near-critical and supercritical semivertex angles. The authors have determined the drag coefficients and the shock position at supersonic flow velocities corresponding to M∞ = 4.0 over a range of cone semivertex angles from 40 to 130 °, at angle of attack α = 0. The experimental drag coefficients are compared with available theoretical values, obtained using both exact and approximate methods of calculation. The experimentally obtained position of the attached shock wave is compared with theory, derived by the method of integral relations in the first approximation.