Download or read book Experimental Study on Mixing Enhancement in Supersonic Stream with Axisymmetric Cavities written by S. Jeyakumar and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Study of the Effect of Streamwise Vorticity on Supersonic Mixing Enhancement written by J. W. Naughton and published by . This book was released on 1989 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 39th AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit July 20 23 2003 Huntsville Alabama 03 4700 written by and published by . This book was released on 2003 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of the Effect of Swirl on Mixing Enhancement of Supersonic Rectangular Jets written by Jason E. Frank 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 Analytical and Experimental Studies on Mixing in Supersonic Flows written by Vijay Gopal and published by . This book was released on 2021 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mixing enhancement in supersonic flow is an important domain of research for enabling the realization of efficient and scalable high speed air-breathing engines (scramjet).Introducing streamwise vorticies in supersonic flow and tailoring their interactions for mixing enhancement is the primary motivation for the present research study. Leveraging the research performed in the group at the Aerodynamics Research Center (ARC), systematic experimental studies on mixing enhancement is carried out in supersonic flows by tailoring the selected modes of stream wise vortex interactions with the aid of in-house developed reduced order method VorTX. This method utilizes the lifting line-vortex theory in supersonic flow to perform rapid simulations of streamwise vortex-interactions that serves as a guide to design the mixing experiments. One of the difficulties associated with scaling the simulations to higher Mach numbers (M > 4) arise from the strong influence of the singularities along the Mach cones emanating from the lifting line-vortex that results in physically inconsistent solution. In this work a fundamental study on vorticity distribution in linearized supersonic flow is carried out. The origin of the aforementioned singularities on the Mach cone is discussed in detail, and the potential candidates for vorticity distribution are proposed to eliminate the singularities and to provide a physically consistent solution of the flow field in supersonic flow. This study presents the successful solution for the elimination of the singularities that has allowed to extend the capability of VorTX to simulate vortex-interactions at higher Mach numbers. Experimental studies on supersonic mixing were carried out using a strut injection platform with vortex generating ramps to introduce streamwise voriticies in supersonic flow. The geometrical configuration of the ramps are chosen using the upgraded VorTX simulations to target the experimental study of two selected modes of vortex interactions. One is the merging of two co-rotating vorticies and the other is the non-merging case where the vorticies interact but do not merge. Mixing measurements in supersonic flow were carried out using the Filtered Rayleigh Scattering (FRS)technique. The measurement yields the mole-fraction of helium (injectant) in a binary mixture of air and helium in supersonic flow. The distributions of helium mole-fraction in the cross flow planes are used to draw conclusions on the level of mixing in the two modes of vortex-interaction. The FRS technique requires two independent experiments. One with helium injection in supersonic air flow and the other with air injection in an identical supersonic air flow. At a given cross-flow plane, to obtain the helium mole-fraction distribution using the FRS signals it is assumed that the total number density is matched in both the experiments. To enhance the reliability of the FRS measurement technique, it is important to minimize and quantify the systematic errors that arise from the assumptions made, particularly, the assumption on matching the total number density. In this work, a method to reduce the systematic errors in FRS experiments is proposed for a canonical case study of a rectangular jet in supersonic flow. To do this, a reduced order model for a rectangular jet in supersonic air flow is successfully developed in order to guide the selection of appropriate injector's plenum conditions to minimize the systematic errors in the future FRS experiments and to retrospectively evaluate and correct the FRS measurements for systematic errors in previously available FRS data on parallel strut injection in supersonic flow.
Download or read book An Experimental Study of the Turbulent Mixing of Subsonic Axisymmetric Gas Streams written by Donald Edward Chriss and published by . This book was released on 1967 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 41st AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit 10 13 July 2005 Tucson Arizona written by and published by . This book was released on 2005 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Experimental Study on Mixing Phenomena in Supersonic Flows with Slot Injection written by S. Aso and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Supersonic Mixing Enhancement by Vorticity for High Speed Propulsion written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-16 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of a three year study on vortex enhancement of supersonic mixing are discussed. Recent interests in compressible mixing has spurred research in the field of high speed shear layers. It was established that shear layer growth diminishes with increasing convective Mach number; this Mach number is the relative Mach number of the large scale structures in the shear layer with respect to the Mach numbers on either side of the shear layer. The purpose was to evaluate the effect of swirl on compressible mixing rates. Previously analytical and experimental results seem to indicate that swirling flow may significantly modify the shear layer, in some cases resulting in enhanced mixing. Previous studies of the effect of swirl on compressible mixing were incomplete since the amount of swirl in the flowfield was not quantified. This study was undertaken to conclusively determine the effect of swirl on supersonic mixing, including the quantification of the swirl. Preliminary results indicate that the swirl modestly enhances the mixing rates. Settles, Gary S. Unspecified Center...
Download or read book Experimental Study of Supersonic Slot Injection Into a Supersonic Stream written by Roger L. Campbell and published by . This book was released on 1987 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2007 with total page 1184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical and Experimental Investigations of the Mixing of a Supersonic Stream with an Induced Secondary Stream as Applied to Ducted Propulsive Devices written by H. L. Pool and published by . This book was released on 1950 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of the Effects of Base Bleed in Axisymmetric Supersonic Flow written by Tarun Mathur and published by . This book was released on 1996 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Base bleed is a technique wherein a small quantity of fluid is injected into the base region of a projectile to reduce the base drag. The effects of base bleed on the near-wake flowfield of a cylindrical afterbody in a Mach 2.5 flow have been investigated in the present study. This experimental study is aimed at better understanding the complex fluid dynamic interactions occurring in the near-wake due to base bleed and is motivated by the lack of detailed velocity and turbulence data in this flowfield. The experimental techniques used include static pressure measurements, schlieren and shadowgraph photography, and two-component laser Doppler velocimetry (LDV). The comprehensive LDV mean velocity and turbulence measurements obtained during this study provide valuable insight into the physics of the base bleed mechanism and constitute a benchmark data set to aid analytical and computational efforts in modeling and predicting supersonic base flows. Static pressure measurements show that with increasing bleed flow rate, the average base pressure increases initially, attains a peak value near an injection parameter of I = 0.0148, and then decreases with further increase in I. The peak base pressure ratio at the optimum bleed condition is 18.5% higher than the blunt base case and 5.7% higher than for a 5 degree boattailed afterbody. Axial LDV traverses show peaks in turbulent kinetic energy along the centerline at the forward and rear stagnation point locations. Centerline measurements also indicate the near-disappearance of the primary recirculation region near the optimum bleed condition. Detailed mean velocity and turbulence data were obtained in the entire near-wake flowfield for three different bleed cases corresponding to low bleed, slightly pre-optimal bleed, and slightly post-optimal bleed conditions. These measurements indicate that the bleed flow provides at least some of the fluid required for shear layer entrainment and shields the base annulus from the outer shear layer and the primary recirculation region, leading to an increase in base pressure. There is an overall reduction in turbulence levels throughout the base bleed flowfields relative to the near-wake flowfields of blunt-based and boattailed afterbodies. With increasing bleed, the formation of a strong bleed jet shear layer and secondary recirculation region near the base annulus offsets the benefits of base bleed, leading to a drop in the base pressure. At all bleed conditions, the normal stress distribution is highly anisotropic with the axial component dominating the near-wake turbulence field. The net benefits of base bleed are maximized at the optimum bleed condition, which corresponds to the highest base pressure, the disappearance of the primary recirculation region, and the lowest turbulence and entrainment levels in the near-wake flowfield.
Download or read book NASA SP written by and published by . This book was released on 1992 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:
