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Investigation Of Pressure Oscillations In Axi Symmetric Cavity Flows
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Book Synopsis Investigation of Pressure Oscillations in Axi-Symmetric Cavity Flows by : V. Sarohia
Download or read book Investigation of Pressure Oscillations in Axi-Symmetric Cavity Flows written by V. Sarohia and published by . This book was released on 1977 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation was conducted of subsonic turbulent flows over shallow, axi-symmetric cavities located downstream of the leading edge of a flat-nosed fuse contour and on an ellipsoidal nose contour. The objective was to evaluate cavity performance in terms of pressure oscillations inside the cavity for various cavity configurations and other pertinent parameters for various modes of cavity operation. Free-stream velocities over the contours ranged up to 650 ft/sec, and Reynolds numbers based on maximum diameter of the contour ranged between 10000 and about 1000000. It was found that pressure signals at the base of the cavity for an oscillating cavity flow as high as 150 dB, could be obtained and that a total acoustic power as high as 20 W was estimated. Furthermore, pressure oscillations existed for cavity depths as small as 0.050 in. It may be that this is not the minimum depth for which oscillations are generated, since the next smaller depth tested was 0.020 in. For the smallest depth, of 0.020 in., pressure oscillations in the cavity did not occur. Cavity oscillations were more pronounced when the cavity was located in the favorable (negative) pressure gradient region of the axi-symmetric body. Instant spark shadowgraphs taken for both laminar and for turbulent boundary layer flow separation at the upstream cavity corner showed the presence of large, organized vortex structures in the oscillating shear layer. Mean velocity measurements of an oscillating cavity shear layer indicated an entrainment rate as large as 0.046 as compared to a non-oscillating cavity shear layer entrainment of approximately 0.021.
Book Synopsis Effect of Angle of Attack on Cavity Flow Oscillations by : V. Sarohia
Download or read book Effect of Angle of Attack on Cavity Flow Oscillations written by V. Sarohia and published by . This book was released on 1978 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Experimental Study of Axisymmetric Cavity Oscillations in Low Speed Incompressible Flow by : Jeremy David Brice Smith
Download or read book An Experimental Study of Axisymmetric Cavity Oscillations in Low Speed Incompressible Flow written by Jeremy David Brice Smith and published by . This book was released on 2005 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1992 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research in Progress written by and published by . This book was released on 1976 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Bibliography by : Jet Propulsion Laboratory (U.S.)
Download or read book Bibliography written by Jet Propulsion Laboratory (U.S.) and published by . This book was released on 1977 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Investigation for Suppressing Flow-induced Pressure Oscillations in an Open Cavity by : Fa-li Yang (CAPT, CAF.)
Download or read book Investigation for Suppressing Flow-induced Pressure Oscillations in an Open Cavity written by Fa-li Yang (CAPT, CAF.) and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Experimental Investigation to Suppress Flow-Induced Pressure Oscillations in Open Cavities by :
Download or read book Experimental Investigation to Suppress Flow-Induced Pressure Oscillations in Open Cavities written by and published by . This book was released on 1989 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: High speed tangential flow over open cavities (e.g. aircraft weapon bays) can invoke large pressure oscillations within the cavity. These large oscillations can damage the cavity structure as well as items placed within the cavity. The purpose of this experimental study was to determine the effectiveness of suppressing pressure oscillations by manipulating the shear layer over a two-dimensional cavity with a length-to-depth ratio of two. Two methods, a frequency controllable control surface (fence) and pulsating secondary airflow at the cavity leading edge, were used to manipulate the shear layer. The suppression effectiveness of the fence utilized in both passive and active modes (zero to 120 Hz) was evaluated at six airflow Mach numbers (0.62, 0.76, 0.90, 1.07, 1.28, 1.53). The effectiveness of pulsating secondary airflow was evaluated at one airflow Mach number (1.28) and two flow injection angles (parallel and 45 degrees to the flow) at frequencies ranging from zero to 80 Hz. The effect of steady flow injection was also evaluated at mass flow rates per unit width ranging from 0.323 to 1.27 (lbm/sec/ft). Pressure recordings from within the cavity were made for each test. The effectiveness of a pulsating fence in suppressing the peak mode pressure oscillations proved to be less than that achievable with the fence static. The pulsed secondary flow injection technique was most effective when pulsed at a 45 degree angle to the external flow. Theses.
Book Synopsis Effect of Finite Cavity Width on the Self-sustained Oscillation in a Low-mach-number Cavity Flow by : Ke Zhang
Download or read book Effect of Finite Cavity Width on the Self-sustained Oscillation in a Low-mach-number Cavity Flow written by Ke Zhang and published by . This book was released on 2009 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Experimental Investigation of Pressure Oscillations in Two- Dimensional Open Cavities by :
Download or read book An Experimental Investigation of Pressure Oscillations in Two- Dimensional Open Cavities written by and published by . This book was released on 1975 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was conducted to determine the characteristics of the pressure oscillations in a small two-dimensional cavity exposed to tangential air flow. Various cavity configuration changes, involving the shape of the leading and trailing edge, were investigated to determine the relative capability to suppress the resonance in the cavity response. Five airflow Mach numbers (0.5, 0.6, 1.0, 1.3, 1.5) were used to investigate the Mach-response relationship. Two cavity lengths were considered (2 and 4 1/4 inches). The depth of the cavities was kept constant at one inch. Fluctuating pressure recordings and schlieren photographs were made of each test.
Book Synopsis An Experimental Investigation Into the Suppression of Flow-induced Pressure Oscillations in Two-dimensional Open Cavities by : Randall S. Mainquist (1LT, USAF.)
Download or read book An Experimental Investigation Into the Suppression of Flow-induced Pressure Oscillations in Two-dimensional Open Cavities written by Randall S. Mainquist (1LT, USAF.) and published by . This book was released on 1978 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis An Experimental Investigation of Open Cavity Pressure Oscillations by : Dennis L. Carr
Download or read book An Experimental Investigation of Open Cavity Pressure Oscillations written by Dennis L. Carr and published by . This book was released on 1974 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was undertaken to investigate the use of a water table to define the parameters that influence the pressure oscillations resulting from air flow over open cavities. Tests were also conducted to investigate means to eliminate or reduce these oscillations. (Author).
Book Synopsis An Experimental Study of Incompressible Axisymmetric Cavity Flow with Swirl by : Lee Charles Wendell
Download or read book An Experimental Study of Incompressible Axisymmetric Cavity Flow with Swirl written by Lee Charles Wendell and published by . This book was released on 2006 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: A systematic study was performed of the flow phenomena in an axisymmetric cavity. Axial flow Reynolds numbers ranged from 100,000 to 530,000 for cavity L/D range of 0.25 to 1.65. Working medium for this study was water reflecting that only incompressible domain of cavity flow was covered in this study. Previous results of axisymmetric flow investigations were reproduced and extended to lower L/D values, with the modified test article. Introduction of swirl in the cavity flow was studied in detail for its effects on the enhancement or suppression of cavity modes that have been measured. The axial apparatus tested here recreated the results of that of the original apparatus. The values of the maximum peaks fell within the range of Helmholtz resonator values at that specific velocity, for a given L/D at and below L/D = 1.05, at the same flow conditions. At and above moderate swirl numbers (S> 0.4), first mode of oscillation was completely suppressed. There was also evidence of a flattening of the remaining trend at higher swirl numbers (S> 0.6). The range of maximum amplitudes experienced in this study was also in agreement with earlier work. Overall, a trend of an increase of the frequency with an increase in swirl was seen in all tests. Generally, the range of greatest increase was for 47.23 ft/s axial flow, with the addition of 38.56 ft/s to 54.54 ft/s of tangential flow. The frequency increase was attributed to the effects of swirl through the range of 0.3
Book Synopsis An Experimental Investigation of Pressure Oscillations in Two-dimensional Open Cavities by : Michael F. Marquardt (CAPT, USAF.)
Download or read book An Experimental Investigation of Pressure Oscillations in Two-dimensional Open Cavities written by Michael F. Marquardt (CAPT, USAF.) and published by . This book was released on 1975 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Adaptive Control of Axisymmetric Jets by Cavities by : Abraham Joseph Meganathan
Download or read book Adaptive Control of Axisymmetric Jets by Cavities written by Abraham Joseph Meganathan and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Actuators capable of producing large amplitude oscillations at desired frequencies are needed in many flow control applications. In this dissertation, turbulent jets were actuated using self-sustaining oscillations in axisymmetric cavities. Tested geometries include baseline turbulent jets passing through axisymmetric cavities, with and without peripheral walls. Cavity length to depth ratio (L [subscript c]/D[subscript c]) was varied from 1 to 5 and data were collected at several intermediate steps. Tests were performed with air over a Reynolds number, based on jet exit diameter, range of 40,000 to 225,000 in low to high subsonic jet flow conditions. Pressure signals, 2D velocity data obtained using Particle Image Velocimetry (PIV) and 2D axisymmetric Computational Fluid Dynamics (CFD) modeling were concurrently used to analyze and understand the problem. Measurements on baseline turbulent jets showed that the near field coherent structures and their residence time are two important factors that could be manipulated to influence the initial growth rate of a jet. Frequency of oscillation of the pressure field within the cavity was primarily dependent on the length scale (length to depth ratio and the pipe diameter) of the cavity and the Mach number of the flow. Axisymmetric cavities with cavity length to depth ratio 1.5 - 2.0, preferably 1.75, placed immediately after the exit of the jet exhibited a resonant condition (between the axial shallow cavity mode and the radial acoustic mode of the pipe) with very high amplitude oscillations (in excess of 180 dB within the cavity) at moderate to high Reynolds number range of this study. Comparison with baseline jets based on centerline velocity decay and lateral jet spread rate showed that mixing characteristics had improved significantly. The potential core length (location of 90% jet exit velocity) for the best case was at 1D as compared to 5D for the baseline jet. Ensemble averages of different phases of an oscillation cycle (along the jet flow direction and in the cross-section) were used to recreate the oscillation cycle (flow visualization images, velocity and vorticity fields) and study the flow structures in the near field. Mode of oscillation (axial / helical) of the jet exiting the cavity was found to be dependent on the inlet and exit boundary conditions of the cavity. Cavities with sharp orifices at the inlet and exit boundaries had complex helical mode structures in the near field of the jet. When the exit boundary of the cavity had a short pipe instead of a sharp orifice, only axial mode vortex rings remained in the near field. However the jet entrainment was not as high, as in the case of sharp orifices.
Book Synopsis Cavity Oscillation in Cruise Missile Carrier Aircraft by : Harold W. Bartel
Download or read book Cavity Oscillation in Cruise Missile Carrier Aircraft written by Harold W. Bartel and published by . This book was released on 1981 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report discusses cavity oscillation in general, and particularly the problem of cavity oscillation in the missile bays of cruise missile carrier aircraft during missile launch. The missile bay configurations analyzed ranged from the complete interior volume of a large transport aircraft, to the bomb bay of a conventional bomber. All of the carrier aircraft cases evaluated were conceptual; no specific airframe models or manufacturers are identified. The principles and technology presented are not limited to missile bays; they are applicable to general cavities having free-stream flow velocities above Mach 0. 4. It is observed that above Mach 0.4 the pressure fluctuations in an oscillating cavity may arise from: (a) sustained periodic pressure fluctuations in the aperture shear layer that radiate noise into the cavity; and (b) sustained periodic pressure fluctuations in the aperture shear layer that couple with the cavity volume acoustic modes (this generally produces by far the most intense cavity oscillation). Theoretical/empirical techniques are presented for predicting oscillatory frequency, pressure level, pressure spatial distribution in the cavity, and the degree of alleviation achievable with suppressors. The information is based on extensive experimentation with subscale models having apertures of 2 to 6 in. in a cold air wall-jet flow facility. A bibliography is included containing 145 listings.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1967 with total page 742 pages. Available in PDF, EPUB and Kindle. Book excerpt:
