Download or read book An Experimental Study of Supersonic Cavity Flow Control with Vertical Rods written by Carolyn Leigh Thiemann and published by . This book was released on 2013 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analysis of an open cavity shear layer when exposed to different leading edge pin configurations was studied experimentally, in a blow-down high speed wind tunnel run at Mach 1.84. A non-intrusive quantitative flow measurement system, Particle Image Velocimetry, was used to study velocity and vorticity fields with and without flow control implementations. The purpose of this study was to attempt to understand and explain the flow mechanisms which cause acoustic suppression obtained using different leading edge, vertical pin configurations. The cavity had an L/D of 4.89 and each pin configuration had a varied number and placement of pins, while pin height remained a constant 1⁄2 inch. The four configurations chosen to be studied were based on the best acoustic suppression results obtained by Milne [4]. To determine and understand the physical mechanism and source of attenuation of this type of cavity flow control technique, this study looked at the acoustic spectrum, velocity vector field data as well as the changes in the velocity and vorticity fields created by each pin configuration. It was determined that a redistribution of the velocity and diffusion of the vorticity in the boundary layer was caused by altering the characteristics of the boundary layer. Vertical pin configurations at the leading edge of a cavity resulted in flow characteristics which bring about a thickening of the shear layer which diffuses the boundary layer vorticity. Certain pin configurations result in various changes in the boundary layer velocity and vorticity redistributions, affecting the shear layer diffusing the boundary layer vorticity. Configurations using staggered pin patterns generated more effectively vorticity diffusion in the shear layer, which lowered the peaks and the broadband in the SPL spectrum. Possible configurations for future testing are also recommended to further study the flow suppression mechanisms.
Download or read book Experimental Investigation of Supersonic Cavity Flows and Their Control written by Ning Zhuang and published by . This book was released on 2007 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of supersonic cavity flows is of interest both from fundamental fluid dynamics and practical perspectives. The complex nature of this flowfield, consisting of compressible shear layers, compression/expansion waves, and fluid-acoustic interactions, makes it a rich problem to study. A detailed experimental study of supersonic flow (M=1.5 to 2) over a range of three-dimensional rectangular cavities (L/D=1 to 5.2) was conducted. The measurements included unsteady surface pressure measurements, particle image velocimetry, and flow visualization using shadowgraph and schlieren. Large-scale structures in the shear layer and a large recirculation zone in the cavity was observed. Spatial and temporal mode switching was also observed, the nature being different for short and long cavities. The shear layer characteristics of the two cavities are very different in term of curvature and growth. Supersonic microjets were used at the leading edge of the cavities to suppress the resonance in the flow. With a minimal mass flux (0.15%), the activation of microjets led to a large reduction in cavity tones (20 dB) and overall sound pressure levels (9dB). In addition, the microjet injection enhanced the shear layer mixing and reduced the velocity fluctuation in the cavities. The significant reductions together with the low mass flux requirements make this a potentially viable technique for full-scale, practical applications.
Download or read book Experimental Study of the Influence of the Boundary Layer Thickness on the Cavity Response in a Supersonic Flow written by Gregoire Boulard and published by . This book was released on 2010 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study of Passive Control of Hypersonic Cavity Flow Oscillations written by D. S. Dolling and published by . This book was released on 1998 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study of open cavity flow has been made in a high Reynolds number, Mach 5 turbulent boundary layer. The majority of measurements made were of fluctuating wall pressures. The objectives were: (1) examine how effective changes in front and rear wall geometry were at attenuating the pressure oscillations, (2) explore how impingement of a shock wave (variable strength and position) the cavity flow, and (3) how stores (different geometries and positions) affected the cavity flow. In addition, techniques which were judged effective at attenuating pressure oscillations for the empty cavity were used with shock impingement and with stores in order to explore their effectiveness under perturbed flow conditions. The results show that vented and slotted walls, and spoilers are ineffective. A 3-D rear wall (swept in both planes and symmetric about the center line) attenuated the strongest oscillations by factors of up to 7 compared to the baseline rectangular cavity. Regardless of shock impingement position, shock strength, store position, store dimensions, store to cavity volume ratio and asymmetric store arrangement the cavity oscillation frequencies remain essentially unchanged. Based on the mean and rms Pressure distributions (whose magnitude varies substantially but whose basic shape does not change significantly) and surface flow patterns it appears that the essential flow structure also remains largely unchanged. These similarities suggest that control techniques developed for the empty cavity flow should be effective with shock impingement or store release. Tests using two passive control rear walls in perturbed cavity flow support this conclusion.
Download or read book Experimental Investigation of Supersonic Internal Cavity Flows written by Kazuyuki Sakamoto and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of Flow Control for Supersonic Inlets written by Neil Titchener and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Study of Supersonic Flow in the Prandtl Nozzle written by J. W. Dolan and published by . This book was released on 1944 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An experimental study of the supersonic flow field over an aeroelastic ogive cylinder model with boundary layer control written by Philip Louis Daily and published by . This book was released on 1969 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of Porous floor Effects on Cavity Flow Fields at Supersonic Speeds written by Floyd Jay Wilcox and published by . This book was released on 1990 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical and Experimental Study of Supersonic Steady Flow Around Inclined Bodies of Revolution written by John V. Rakich and published by . This book was released on 1969 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Study of the Supersonic Flow Around V Shaped Wings written by A. L. Gonor and published by . This book was released on 1978 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of Porous floor Effects on Cavity Flow Fields at Supersonic Speeds written by Floyd J. Wilcox and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large eddy Simulation of Supersonic Cavity Flowfields Including Flow Control written by D. P. Rizzetta and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental and Computational Study of Unsteady Supersonic 2 D Open Cavity Flow Physics written by Douglas W. Dusing and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study of Supersonic Flows Over an Elliptic Cone written by M. Samimy and published by . This book was released on 1999 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: An elliptic cone similar to the one used by other investigators, a 4:1 aspect ratio elliptic cone with the cone angle on the major axis of 17.5 deg and 4.5 deg along the minor axis, in a Mach 2.8 tunnel was used in the present work. The Reynolds number used in this work was much higher than that used in other experimental work. The purpose is to examine the transition process as well as the turbulent structure of a three-dimensional boundary layer after transition. The primary focus of this study is on the structure of the turbulence, which was explored using advanced optical diagnostics. Both surface flow visualizations and Filtered Rayleigh Scattering (FRS) based flow visualizations were used in this study. The results showed that the boundary layer developing along the major centerline, the flattest region on the cone surface, underwent transition to turbulence approximately 35 mm downstream of the cone tip. Surface cross flow was observed primarily near the minor centerline of the cone, the area with the largest curvature. No cross flow was observed around the major centerline after 10 mm downstream of the cone tip.
Download or read book An Experimental Investigation of Cavity Vortex Generators in Supersonic Flow written by Richard Hazlewood and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Study on the Supersonic Flow Around Blunt nosed Bodies of Revolution written by Hakuro Oguchi and published by . This book was released on 1959 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
