Download or read book A Prediction Method for Turbulent Boundary Layers in Adverse Pressure Gradients written by W. H. Schofield and published by . This book was released on 1981 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: A prediction method for turbulent boundary layers in moderate to strong adverse pressure gradients is presented. The closure hypothesis for the method is the universal velocity defect law of Schofield and Perry (1972) which restricts the method to the prediction of layers in moderate to strong adverse pressure gradient. The method is tested against nine experimentally measured boundary layers. Predictions for velocity profile shape, boundary layer thicknesses and velocity scale ratio were generally in good agreement with the experimental measurements and were superior to those given by other prediction methods. Unlike other methods the present method also gives reasonably accurate predictions for the shear stress profile of a layer. The analysis presented here is compared with previous work and helps to resolve some disagreements discerned in the literature.
Download or read book Method for Predicting Compressible Turbulent Boundary Layers in Adverse Pressure Gradients written by Shimer Zane Pinckney and published by . This book was released on 1971 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Prediction Method for the Calculation of Boundary Layer Parameters for a Turbulent Boundary Layer Under Free stream Turbulence for Zero and Adverse Pressure Gradients written by Kevin Michael Mejia and published by . This book was released on 1991 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Procedure for Calculating the Development of Turbulent Boundary Layers Under the Influence of Adverse Pressure Gradients written by Kennedy F. Rubert and published by . This book was released on 1951 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: A procedure based on the kinetic-energy equation and an extended form of the momentum equation has been devised for calculating the development of turbulent boundary layers in adverse pressure gradients. Predictions, by this method, of turbulent-boundary-layer developement in comparison with experimental results from several sources are presented for a number of cases of flow over flat plates and airfoils and in conical diffusers. In the range of boundary-layer flow short of separation, the agreement with experiment is, in most cases, quite satisfactory; in some instances, however, there is definite disagreement between the calculated and experimental results. It is believed, however, that good agreement has been obtained of effort along the present lines, particularly with respect to improvement of the correlations and refinement of the equations.
Download or read book An Integral Method for the Prediction of Turbulent Boundary Layer Development Using Separate Velocity and Shear Stress Profiles written by H. D. Harris and published by . This book was released on 1970 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Turbulent Boundary Layers written by Tuncer Cebeci and published by Elsevier. This book was released on 2012-12-02 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analysis of Turbulent Boundary Layers focuses on turbulent flows meeting the requirements for the boundary-layer or thin-shear-layer approximations. Its approach is devising relatively fundamental, and often subtle, empirical engineering correlations, which are then introduced into various forms of describing equations for final solution. After introducing the topic on turbulence, the book examines the conservation equations for compressible turbulent flows, boundary-layer equations, and general behavior of turbulent boundary layers. The latter chapters describe the CS method for calculating two-dimensional and axisymmetric laminar and turbulent boundary layers. This book will be useful to readers who have advanced knowledge in fluid mechanics, especially to engineers who study the important problems of design.
Download or read book The Behavior of Turbulent Boundary Layers in Adverse Pressure Gradients written by Hal L. Moses and published by . This book was released on 1964 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: The problem of predicting the behavior of the incompressible turbulent boundary layer in an adverse pressure gradient is re-examined. An outline of the problem is given along with a brief summary of the work that has already been done, including both experimental investigation are presented for a separating turbulent boundary layer with various pressure distributions. An approximate theory is developed in which the momentum integral equation is satisfied for each half of the boundary layer. The velocity profiles used in the analysis consist of the well known wall and wake regions, resulting in a two-parameter family with the Reynolds number as one parameter. It is assumed, with some experimental justification, that the eddy viscosity can be reasonably approximated from zero pressure gradient experimets. The numerical calculations, using the Runge-Kutta procedure, show good agreement with the experiments. The reliability that can be expected of such approximate methods is discussed. (Author).
Download or read book Application of Head s Entrainment Method to the Prediction of Turbulent Boundary Layers and Wakes in Compressible Flow written by J. E. Green and published by . This book was released on 1972 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Three dimensional Turbulent Boundary Layers written by A. J. Wheeler and published by . This book was released on 1971 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predicting Turbulent Boundary Layer Wall Pressure Fluctuations in Adverse Pressure Gradients written by Frank J. Aldrich and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluation of Analytical Procedures for Prediction of Turbulent Boundary Layers on a Porous Wall written by Charles E. Towne and published by . This book was released on 1974 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Boundary Layers written by Alec David Young and published by AIAA (American Institute of Aeronautics & Astronautics). This book was released on 1989 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Following an introduction to the basic physical concepts and the theoretical framework of boundary layers, discussion includes laminar boundary layers, the physics of the transition from laminar to turbulent flow, the turbulent boundary layer and its governing equations in time-averaging form, drag prediction by integral methods, turbulence modeling and differential methods, and current topics and problems in research and industry.
Download or read book An Integral Prediction Method for Turbulent Boundary Layers Using the Turbulent Kinetic Energy Equation written by E. A. Hirst and published by . This book was released on 1968 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new integral method was devised for predicting the development of two-dimensional, incompressible, stationary turbulent boundary layers. This new method differs from the older integral methods in that it explicitly accounts for the turbulence via a characteristic turbulent velocity scale. A model of the turbulent kinetic energy integral equation is used to keep track of this turbulence scale. The model equation is developed on the basis of intuition, physical reasoning and some experimental evidence. In this new method the model equation is solved in conjunction with the momentum integral equation and the entrainment equation. A two-layer velocity profile is used. The law of the wall is assumed valid in the inner region and Coles' law of the wake is assumed valid in the outer region. The two profiles are joined by asymptotic matching; this gives an implicit equation for the skin friction. The predictions using this method are in excellent agreement with the measurements for fourteen different experimental boundary layers. (Author).
Download or read book Computation of Turbulent Boundary Layers 1968 AFOSR IFP Stanford Conference written by Stephen Jay Kline and published by . This book was released on 1969 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Improved Reynolds Stress Modeling for Adverse Pressure Gradient Turbulent Boundary Layers in Industrial Aeronautical Flow written by Gustave Sporschill and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work seeks to improve the prediction of turbulent boundary layer flows under adverse pressure gradients (APG) encountered in the aeronautical industry, especially towards the trailing edge of wings. Indeed, the inaccurate prediction of such flows results in inaccurate predictions of aircraft performance and of the limits of the flight domain. To reduce the design margins and enable optimal aircraft geometries, the reliability of turbulence models in APG boundary layers has to be improved.The relevance of second-moment closures of the RANS equations, also called Reynolds-stress models (RSM), aiming at reproducing more accurately the physics of the flow, is therefore assessed for industrial use. Three Reynolds-stress models that differ in their near-wall modelling and in their length-scale providing equation, namely the EB-RSM, the SSG/LRR-omega RSM and the SSG-omega ATAAC RSM, are first benchmarked on two academic test cases, a flat plate and the APG boundary layer at equilibrium of the Skåre & Krogstad experiment, against the Spalart-Allmaras model and the reference data. These academic cases highlight the fundamental differences between the models and their impact on the profiles and integral quantities of the boundary layer. In particular, the Reynolds-stress profiles and the turbulence budgets in the flat plate test case demonstrate the effectiveness of near-wall modelling. However, the Skåre & Krogstad test case shows the necessity to improve the prediction of velocity profiles in the log region and of skin friction in strong APG flows, despite an excellent prediction of the boundary layer growth.A correction for the log-law region, corresponding to a local recalibration of the model constants in APG regions, is first explored to ensure the correct velocity gradient in APG log layers. The correction is investigated with the Spalart-Allmaras model using a NACA 4412 test case. Despite satisfactory results, the correction is shown to be difficult to generalise to other models and that its impact on the flow prediction is limited to low-Reynolds-number cases, thus restricting its relevance for the aeronautical industry.The two-equation eddy-viscosity models and RSMs are shown to be incompatible with the square-root layer, which progressively grows at the outer end of the log layer in APG boundary layers. A correction locally introducing a pressure-diffusion term is therefore investigated analytically and assessed on the RSMs considered using the Skåre & Krogstad test case. A new model, the EB-RSM-dP, is here defined as a corrected version of the EB-RSM and exhibits improved predictions regarding the velocity and Reynolds-stress profiles and the boundary layer quantities.The standard and corrected RSMs are compared to the Spalart-Allmaras model on an application case, the Common Research Model, representative of a commercial aircraft, and demonstrate the relevance of such models for the aeronautical industry with improved pressure distribution on the wing and reduced errors in the drag-due-to-lift predictions. The square-root-law correction is here validated with the SSG/LRR-omega-dP of Knopp et al. (2018) and the newly developed EB-RSM-dP, and shows significant improvement of the aerodynamic load on the wing, and of both the lift and drag predictions for the highest Reynolds number configuration, compared to the uncorrected models. This study also highlights the strong impact of the activation region of the correction on the results.
Download or read book Calculation of Compressible Turbulent Boundary Layers with Pressure Gradients and Heat Transfer written by Larry L. Lynes and published by . This book was released on 1969 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Method for the Calculation of the Turbulent Boundary Layer in a Pressure Gradient written by Paul S. Granville and published by . This book was released on 1951 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
