The Experts below are selected from a list of 195 Experts worldwide ranked by ideXlab platform
E.v. Shishov - One of the best experts on this subject based on the ideXlab platform.
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Turbulent heat and momentum transfer in boundary layers under Strong Pressure Gradient conditions - Analysis of experimental data and numerical prediction
Experimental Thermal and Fluid Science, 1991Co-Authors: E.v. ShishovAbstract:Abstract The results of experimental investigation of the structure, including correlations containing Pressure fluctuations, and the process of turbulent transfer of heat and momentum in Strongly accelerated and retarded turbulent boundary layers are presented. Based on the analysis of the data obtained, modified algebraic “ K-ϵ ” model, capable of predicting local friction and heat transfer in boundary layers developing under Strong positive and negative Pressure Gradients, is proposed.
Tuncer Cebeci - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Turbulent Flows - Algebraic Turbulence Models
Analysis of Turbulent Flows, 2004Co-Authors: Tuncer CebeciAbstract:In this chapter are discussed algebraic models suitable for calculating turbulent boundary layers, transport coefficients that account for various effects such as Pressure Gradient and heat and mass transfer. The eddy-viscosity and mixing-length models are presented, then the Cebeci-Smith (CS) model is discussed in some detail for momentum and heat transfer, taking account of the effects of low Reynolds number, transverse curvature, streamwise wall curvature, natural transition and roughness. The CS model is then extended to Strong Pressure-Gradient flows using the Johnson-King and Cebeci-Chang approaches, and further for application to Navier-Stokes methods. The chapter concludes with an examination of eddy conductivity and turbulent Prandtl number models, and the use of the CS model for three-dimensional flows.
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Predicting Stall and Post-Stall Behavior of Airfoils at Low Mach Numbers
AIAA Journal, 1995Co-Authors: Tuncer Cebeci, Hamid Hefazi, Farzam Roknaldin, Lawrence W. CarrAbstract:An interactive boundary-layer method, together with the e"approach to the calculation of transition, is used to predict the stall and post-stall behavior of airfoils in incompressible and compressible flows at low freestream Mach numbers. Two separate inviscid methods—a panel method with compressibility corrections and a full potential method—are used to compute the external velocity distribution needed in the solution of the compressible boundary-layer equations. The turbulence model is based on the Cebeci-Smith algebraic eddy-viscosity formulation with improvements for Strong Pressure Gradient effects. Comparison of calculated results with inviscid flow computed with a panel method indicate excellent agreement with experiment for a wide range of Reynolds numbers in incompressible flows. Comparison of calculated results obtained with inviscid flow computed with a full potential method also indicate excellent agreement with experiment for a wide range of angles of attack, including stall for compressible flows at low freestream Mach numbers. The study also shows that even though the compressibility corrections to the panel method are adequate at small-to-moderate angles of attack, they are not satisfactory at higher angles of attack, especially near stall.
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Prediction of stall and post-stall behavior of airfoils at low and high Reynolds numbers
11th Applied Aerodynamics Conference, 1993Co-Authors: Tuncer Cebeci, Farzam Roknaldin, Lawrence W. CarrAbstract:An interactive boundary-layer method, together with the e(super n)-approach to the calculation of transition, has been used to predict the stall and post-stall behavior of airfoils at low and high Reynolds numbers. The turbulence model is based on the Cebeci-Smith algebraic eddy-viscosity formulation with improvements for Strong Pressure Gradient effects and transitional flows at low Reynolds numbers. Comparison of calculated results for incompressible flows indicate good agreement with experiment for a wide range of Reynolds numbers. Preliminary calculations for low Mach number flows with this interactive method with compressibility corrections to the panel method indicate that, at a Mach number of 0.3, the compressibility effect on (C sub Q)max is not negligible.
Lawrence W. Carr - One of the best experts on this subject based on the ideXlab platform.
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Predicting Stall and Post-Stall Behavior of Airfoils at Low Mach Numbers
AIAA Journal, 1995Co-Authors: Tuncer Cebeci, Hamid Hefazi, Farzam Roknaldin, Lawrence W. CarrAbstract:An interactive boundary-layer method, together with the e"approach to the calculation of transition, is used to predict the stall and post-stall behavior of airfoils in incompressible and compressible flows at low freestream Mach numbers. Two separate inviscid methods—a panel method with compressibility corrections and a full potential method—are used to compute the external velocity distribution needed in the solution of the compressible boundary-layer equations. The turbulence model is based on the Cebeci-Smith algebraic eddy-viscosity formulation with improvements for Strong Pressure Gradient effects. Comparison of calculated results with inviscid flow computed with a panel method indicate excellent agreement with experiment for a wide range of Reynolds numbers in incompressible flows. Comparison of calculated results obtained with inviscid flow computed with a full potential method also indicate excellent agreement with experiment for a wide range of angles of attack, including stall for compressible flows at low freestream Mach numbers. The study also shows that even though the compressibility corrections to the panel method are adequate at small-to-moderate angles of attack, they are not satisfactory at higher angles of attack, especially near stall.
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Prediction of stall and post-stall behavior of airfoils at low and high Reynolds numbers
11th Applied Aerodynamics Conference, 1993Co-Authors: Tuncer Cebeci, Farzam Roknaldin, Lawrence W. CarrAbstract:An interactive boundary-layer method, together with the e(super n)-approach to the calculation of transition, has been used to predict the stall and post-stall behavior of airfoils at low and high Reynolds numbers. The turbulence model is based on the Cebeci-Smith algebraic eddy-viscosity formulation with improvements for Strong Pressure Gradient effects and transitional flows at low Reynolds numbers. Comparison of calculated results for incompressible flows indicate good agreement with experiment for a wide range of Reynolds numbers. Preliminary calculations for low Mach number flows with this interactive method with compressibility corrections to the panel method indicate that, at a Mach number of 0.3, the compressibility effect on (C sub Q)max is not negligible.
Aruna Nayak - One of the best experts on this subject based on the ideXlab platform.
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Flow mixing and electric potential effect of binary fluids in micro/nano channels
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2017Co-Authors: Aruna Nayak, Aeraj Ul Haque, A. Banerjee, Bernhard WeigandAbstract:Abstract In the present study, mixing enhancement is analyzed due to the multi component species transport with the variation of surface potential. The formation of vortices along the flow region due to wall heterogeneity and the solution molarity of a circular channel is discussed. The numerical solutions are obtained using the coupled Nernst–Planck equation, the Poisson equation, and the Navier–Stokes equations. A finite volume based approach is adopted to compute the mass, potential and flow profiles using Nernst–Plank model which can be valid for higher surface potential. A flow recirculation is induced due to the Strong Pressure Gradient at the overpotential region which increases the mixing performance. The streamlines and mole fraction distribution follows a tortuous path above the non-uniform potential and the flow properties of Strong solution deviates more compared to weaker solution due to induced Pressure Gradient which is created by the flow phase difference.
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Analysis of mixing for electroosmotic flow in micro/nano channels with heterogeneous surface potential
International Journal of Heat and Mass Transfer, 2014Co-Authors: Aruna NayakAbstract:Abstract Electroosmotic flow in micro and nano channels deals with the low Reynolds number effects due to weak inertial forces. It requires a very long channel for mixing of different species in low Reynolds number through diffusion. The motivation of the present study is to increase the mixing performance when more than one species with heterogeneous surface potential is considered. The generation of vortical flow due to the presence of wall heterogeneity at different locations of the channel is discussed. The flow characteristics for the present study are obtained by numerical solution of the Poisson equation, the Nernst–Planck equation, and the Navier–Stokes equation, simultaneously. A numerical method based on the Pressure correction iterative algorithm (SIMPLE) is adopted to compute the flow field and mole fraction of the ions. The potential patch along the channel walls induces a Strong recirculation vortex which in turn generate a Strong Pressure Gradient to increase the mixing performance. The streamlines follow a tortuous path near patches.
Xinwei Wang - One of the best experts on this subject based on the ideXlab platform.
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Secondary shock wave in laser-material interaction
Journal of Applied Physics, 2008Co-Authors: Sobieslaw Gacek, Xinwei WangAbstract:In this work, the effects of shock driven process of the laser-ablated argon plume in a background gas environment are explored via molecular dynamics simulations. The primary shock wave propagation and its influence on the backward motion of the target material are delineated. It is observed that the Strong Pressure Gradient inside the main shock wave overcomes the forward momentum of the plume and some compressed gas, leading to backward movement and redeposition on the target surface. Reflection of the backward moving gas on the target surface results in the secondary shock wave. Detailed investigation of the secondary shock wave phenomenon is provided, which gives, for the first time, an insight into formation and evolution of the internal gaseous shock at the atomistic level.
