Download or read book Engineering Model of Unsteady Flow in a Cavity written by R. C. Bauer and published by . This book was released on 1991 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: A mathematical model was assembled from fundamental fluid dynamic relations and turbulent single-stream mixing zone relations to predict spectra, i.e., the frequency and amplitude, of unsteady pressures acting in a rectangular cavity exposed to an external flow parallel to the cavity opening. Characteristics of the approaching boundary layer are expected as inputs, thereby allowing computation of spectra for cases of mass-injection upstream of the cavity. The equations were compiled as a code (CAP) that can be run in less than 15 sec on a personal computer. Maximum dynamic loads acting on the contents of the cavity can be estimated, in addition to the primary frequencies of oscillation.

Download or read book Engineering Model of Unsteady Flow in a Cavity written by and published by . This book was released on 1991 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: A mathematical model was assembled from fundamental fluid dynamic relations and turbulent single-stream mixing zone relations to predict spectra, i.e., the frequency and amplitude, of unsteady pressures acting in a rectangular cavity exposed to an external flow parallel to the cavity opening. Characteristics of the approaching boundary layer are expected as inputs, thereby allowing computation of spectra for cases of mass-injection upstream of the cavity. The equations were compiled as a code (CAP) that can be run in less that 15 sec on a personal computer. Maximum dynamic loads acting on the contents of the cavity can be estimated, in addition to the primary frequencies of oscillation.

Download or read book Experimental and Theoretical Study of Cavity Acoustics written by R. E. Dix and published by . This book was released on 2000 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: Between 1986 and 1990, a large database was compiled at AEDC from the results of a series of wind tunnel experiments investigating the aerodynamics of flow over open cavities. The database, known as the Weapons Internal Carriage and Separation (WICS) database, covered four experiments that were completed in the AEDC wind tunnels. The initial database documentation focused on the test and data, but included very little analysis of the results. The purpose of the present work is to report analysis of the cavity acoustics and trajectory data. In addition, an updated engineering mathematical model for cavity aeroacoustics is presented.

Download or read book Unsteady Flow Over a Rectangular Cavity written by Richard Michael Forristal and published by . This book was released on 2000 with total page 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 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unsteady Laminar and Turbulent Cavity Flow Models by Second Order Upwind Methods written by A. Rona and published by . This book was released on 1999 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book General Formulation of a Perturbation Theory for Unsteady Cavity Flows written by D. P. Wang and published by . This book was released on 1965 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The problem of a two-dimensional cavity flow of an ideal fluid with small unsteady disturbances in a gravity free field is considered. By regarding the unsteady motion as a small perturbation of an established steady cavity flow, a fundamental formulation of the problem is presented. It is shown that the unsteady disturbance generates a surface wave propagating downstream along the free cavity boundary, much in the same way as the classical gravity waves in water, only with the centrifugal acceleration owing to the curvature of the streamlines in the basic flow playing the role of an equivalent gravity effect. As a particularly simple example, the surface waves in a hollow potential vortex flow is calculated by using the present theory. (Author).

Download or read book Unsteady Computational Fluid Dynamics in Aeronautics written by P.G. Tucker and published by Springer Science & Business Media. This book was released on 2013-08-30 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of Large Eddy Simulation (LES) and hybrids is a vibrant research area. This book runs through all the potential unsteady modelling fidelity ranges, from low-order to LES. The latter is probably the highest fidelity for practical aerospace systems modelling. Cutting edge new frontiers are defined. One example of a pressing environmental concern is noise. For the accurate prediction of this, unsteady modelling is needed. Hence computational aeroacoustics is explored. It is also emerging that there is a critical need for coupled simulations. Hence, this area is also considered and the tensions of utilizing such simulations with the already expensive LES. This work has relevance to the general field of CFD and LES and to a wide variety of non-aerospace aerodynamic systems (e.g. cars, submarines, ships, electronics, buildings). Topics treated include unsteady flow techniques; LES and hybrids; general numerical methods; computational aeroacoustics; computational aeroelasticity; coupled simulations and turbulence and its modelling (LES, RANS, transition, VLES, URANS). The volume concludes by pointing forward to future horizons and in particular the industrial use of LES. The writing style is accessible and useful to both academics and industrial practitioners. From the reviews: "Tucker's volume provides a very welcome, concise discussion of current capabilities for simulating and modellng unsteady aerodynamic flows. It covers the various pos sible numerical techniques in good, clear detail and presents a very wide range of practical applications; beautifully illustrated in many cases. This book thus provides a valuable text for practicing engineers, a rich source of background information for students and those new to this area of Research & Development, and an excellent state-of-the-art review for others. A great achievement." Mark Savill FHEA, FRAeS, C.Eng, Professor of Computational Aerodynamics Design & Head of Power & Propulsion Sciences, Department of Power & Propulsion, School of Engineering, Cranfield University, Bedfordshire, U.K. "This is a very useful book with a wide coverage of many aspects in unsteady aerodynamics method development and applications for internal and external flows." L. He, Rolls-Royce/RAEng Chair of Computational Aerothermal Engineering, Oxford University, U.K. "This comprehensive book ranges from classical concepts in both numerical methods and turbulence modelling approaches for the beginner to latest state-of-the-art for the advanced practitioner and constitutes an extremely valuable contribution to the specific Computational Fluid Dynamics literature in Aeronautics. Student and expert alike will benefit greatly by reading it from cover to cover." Sébastien Deck, Onera, Meudon, France

Download or read book Forum on Unsteady Flow 1988 written by Paul H. Rothe and published by . This book was released on 1988 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Three dimensional Flow in Cavity at Yaw written by Alex Povitsky and published by . This book was released on 2001 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study is motivated by three-dimensional flows about protrusions and cavities with an arbitrary angle between the external flow and rigid elements. The novel type of a "building block" cavity flow is proposed where the cavity lid moves along its diagonal (Case A). The proposed case is taken as a typical representative of essentially three-dimensional highly separated vortical flows having simple single-block rectangular geometry of computational domain. Computational results are compared to the previous studies where the lid moves parallel to the cavity side walls (Case B). These 3-D lid-driven cavity flows are studied by numerical modeling using second-order upwind schemes for convective terms. The volume and plane integrals of primary and transversal momentum are introduced to compare cases in a quantitative way. For the laminar flow in the cubic cavity, the integral momentum of the secondary flow (which is perpendicular to the lid direction) is about an order of magnitude larger than that in Case B. In Case A, the number of secondary vortices substantially depends on the Re number. The secondary vortices in the central part of the cavity in Case A distinguishes it from Case B, where only corner secondary vortices appear. For a rectangular 3-D 3: 1 : 1 cavity the integral momentum of the secondary flow in Case A is an order of magnitude larger than that in the benchmark cases. The flow field in Case A includes a curvilinear separation line and non-symmetrical vortices which are discussed in the paper. The estimated Goertler number is approximately 4.5 times larger in Case A than that in Case B for the same Re number. This indicates that in Case A the flow becomes unsteady for smaller Re numbers than in Case B. For developed turbulent flow in the cubic cavity, the yaw effect on amplifcation of secondary flow is as strong as that for the laminar flow despite the more complex vortical flow pattern in benchmark case B.

Download or read book Numerical Method for Steady state Cavity Flows written by Stanford University. Department of Civil Engineering and published by . This book was released on 1972 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the work was to develop a numerical method for steady-state cavity flows to provide systematic correction of an initial, assumed free streamline position. The method is based on an inviscid, irrotational and incompressible flowfield, uses a numerical finite-difference representation with the fluid velocities as dependent variables, and obtains a solution by successive-overrelaxation. It has been implemented for two-dimensional fully cavitating flow past a vertical plate in a channel. Typical results and the computer program listing and output are given. (Author).

Download or read book Unsteady Flow in Rectangular Cavities written by L. F. East and published by . This book was released on 1965 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modeling Unsteady Cavity Flows with Translating Walls written by B. Lukovic 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 Unsteady Symmetrical Supercavitating Flows Past a Thin Wedge in a Jet written by C. S. Song and published by . This book was released on 1962 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: Problems of symmetrical two-dimensional supercavitating flow about a thin wedge in a finite fluid with two free surfaces are solved by means of a linearized method utilizing the complex acceleration potential. Taking advantage of the symmetry, the otherwise doubly connected region is divided into two identical simply connected regions. An oscillatory-type motion as well as general types of unsteady motions are considered. The solution contains no singularity and, as a result, pressure is everywhere finite. The mathematical condition required for the existence of a singularity-free solution leads to an equation which gives the relationship between the cavity length and the cavitation number. The theoretical results are in good agreement with experimental data for the steadyflow case, but data for the unsteady case are not yet available. (Author).

Download or read book Scramjets written by Mostafa Barzegar Gerdroodbary and published by Butterworth-Heinemann. This book was released on 2020-07-21 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scramjet engines are a type of jet engine and rely on the combustion of fuel and an oxidizer to produce thrust. While scramjets are conceptually simple, actual implementation is limited by extreme technical challenges. Hypersonic flight within the atmosphere generates immense drag, and temperatures found on the aircraft and within the engine can be much greater than that of the surrounding air. Maintaining combustion in the supersonic flow presents additional challenges, as the fuel must be injected, mixed, ignited, and burned within milliseconds. Fuel mixing, along with the configuration and positioning of the injectors and the boundary conditions, play a key role in combustion efficiency. Scramjets: Fuel Mixing and Injection Systems discusses how fuel mixing efficiency and the advantage of injection systems can enhance the performance of the scramjets. The book begins with the introduction of the supersonic combustion chamber and explains the main parameters on the mixing rate. The configuration of scramjets is then introduced with special emphasis on the main effective parameters on the mixing of fuel inside the scramjets. In addition, basic concepts and principles on the mixing rate and fuel distribution within scramjets are presented. Main effective parameters such as range of fuel concentration for the efficient combustion, pressure of fuel jet and various arrangement of jet injections are also explained. This book is for aeronautical and mechanical engineers as well as those working in supersonic combustion who need to know the effects of compressibility on combustion, of shocks on mixing and on chemical reactions, and vorticity on the flame anchoring. Explains the main applicable approaches for enhancement of supersonic combustion engines and the new techniques of fuel injection Shows how the interaction of main air stream with fuel injections can develop the mixing inside the scramjets Presents results of numerical simulations and how they can be used for the development of the combustion engines

Download or read book Embedded Cavity Drag in Steady and Unsteady Flows written by T. B. Gatski and published by . This book was released on 1983 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fluid Dynamics of Unsteady Cavity Flow written by and published by . This book was released on 1996 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unsteady, hypersonic flow over the nose of a blunt body with a forward-facing cavity is studied. A parameter study is conducted using a commercial finite-volume computer code to study the mechanisms of resonance. Numerical simulation results are often directly compared to recent experiments. Resonant pressure oscillations within the cavity occur for relatively shallow cavities provided freestream noise is present. However, deeper cavities self-sustain strong resonance. A spring-mass-damper model is described which emulates noise-driven, relatively shallow cavity acoustic behavior.