A Reynolds Stress Relaxation Turbulence Model Applied to A Wingtip Vortex Flow

2011 ◽  
Author(s):  
Matthew Churchfield ◽  
Gregory Blaisdell
Keyword(s):  
Stress Relaxation ◽  
Reynolds Stress ◽  
Turbulence Model ◽  
Vortex Flow ◽  
Wingtip Vortex

Reynolds Stress Relaxation Turbulence Modeling Applied to a Wingtip Vortex Flow

AIAA Journal ◽  
2013 ◽  
Vol 51 (11) ◽  
pp. 2643-2655 ◽  
Author(s):  
Matthew J. Churchfield ◽  
Gregory A. Blaisdell
Keyword(s):  
Stress Relaxation ◽  
Reynolds Stress ◽  
Vortex Flow ◽  
Turbulence Modeling ◽  
Wingtip Vortex

scholarly journals THERMODYNAMIC ANALYSIS OF WIND CATCHER WITH COOLING PADS USING SSG REYNOLDS STRESS TURBULENCE MODEL.

2021 ◽  
Author(s):  
Agarwal A ◽  
◽  
Pitso I ◽  
Letsatsi M.T ◽  
◽  
...  
Keyword(s):  
Reynolds Stress ◽  
Turbulence Model ◽  
Energy Requirement ◽  
Renewable Energy Sources ◽  
Thermal Conditions ◽  
Energy Sources ◽  
Cfd Analysis ◽  
Open Design ◽  
Air Inlet ◽  
Environment Sustainability

With increase in energy requirement, the researchers are looking for energy efficient passive ventilation techniques. The current design concept is based on environment sustainability and use of renewable energy sources is preferred over conventional energy sources. The current research investigates the wind catcher design with cooling pads using techniques of Computational Fluid Dynamics. The CAD model of wind catcher is designed using Creo design software and CFD analysis is conducted using ANSYS CFX software. The CFD analysis is directed at different air inlet velocities and SSG Reynolds stress turbulence model under steady state thermal conditions for both side open design and singe side open designs. The cooling pads have successfully reduced temperature up to 1.65 degrees for single side opening and 2.86 degrees for double side opening design. Maximum air flow rate is achieved with higher air inlet velocities for both design types.

Numerical Experiments for Flow Around a Ducted Tip Hydrofoil

2002 ◽  
Author(s):  
Hildur Ingvarsdo´ttir ◽  
Carl Ollivier-Gooch ◽  
Sheldon I. Green
Keyword(s):  
Turbulence Model ◽  
Vortex Core ◽  
Vortex Flow ◽  
Computational Study ◽  
Near Field ◽  
Vortex Formation ◽  
Tip Vortex ◽  
Navier Stokes ◽  
Computational Studies ◽  
Tip Vortices

The performance and cavitation characteristics of marine propellers and hydrofoils are strongly affected by tip vortex behavior. A number of previous computational studies have been done on tip vortices, both in aerodynamic and marine applications. The focus, however, has primarily been on validating methods for prediction and advancing the understanding of tip-vortex formation in general, rather than showing effects of tip modifications on tip vortices. Studies of the most relevance to the current work include computational studies by Dacles-Mariani et al. (1995) and Hsiao and Pauley (1998, 1999). Daeles-Mariani et al. carried out interactively a computational and experimental study of the wingtip vortex in the near field using a full Navier-Stokes simulation, accompanied with the Baldwin-Barth turbulence model. Although they showed improvement over numerical results obtained by previous researchers, the tip vortex strength was underpredicted. Hsiao and Pauley (1998) studied the steady-state tip vortex flow over a finite-span hydrofoil, also using the Baldwin-Barth turbulence model. They were able to achieve good agreement in pressure distribution and oil flow pattern with experimental data and accurately predict vertical and axial velocities of the tip vortex core within the near-field region. Far downstream, however, the computed flow field was overly diffused within the tip vortex core. Hsiao and Pauley (1999) also carried out a computational study of the tip vortex flow generated by a marine propeller. The general characteristics of the flow were well predicted but the vortex core was again overly diffused.

Passive Wingtip Vortex Control by Using Tip-Mounted Half Delta Wings in Ground Effect

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Anan Lu ◽  
Tim Lee
Keyword(s):  
Vortex Flow ◽  
Ground Effect ◽  
Tip Vortex ◽  
Secondary Vortex ◽  
Flow Properties ◽  
Delta Wings ◽  
Vortex Control ◽  
Physical Mechanisms ◽  
Induced Drag ◽  
Wingtip Vortex

Abstract The ground effect on the wingtip vortex generated by a rectangular semiwing equipped with tip-mounted regular and reverse half delta wings was investigated experimentally. The passive tip vortex control always led to a reduced lift-induced drag as the ground was approached. In close ground proximity, the presence of the corotating ground vortex (GV) added vorticity to the tip vortex while the counter-rotating secondary vortex (SV) negated its vorticity level. The interaction of the GV and SV with the tip vortex and their impact on the lift-induced drag were discussed. Physical mechanisms responsible for the change in the vortex flow properties in ground effect were also provided.

scholarly journals A Second-Order Turbulence Model Based on a Reynolds Stress Approach for Two-Phase Flow—Part I: Adiabatic Cases

2009 ◽  
Vol 2009 ◽  
pp. 1-14 ◽  
Author(s):  
S. Mimouni ◽  
F. Archambeau ◽  
M. Boucker ◽  
J. Laviéville ◽  
C. Morel
Keyword(s):  
Liquid Phase ◽  
Reynolds Stress ◽  
Turbulence Model ◽  
Two Phase Flow ◽  
Turbulence Modeling ◽  
Transport Model ◽  
Phase Flow ◽  
Two Phase ◽  
Model Based ◽  
Reynolds Stress Transport Model

In our work in 2008, we evaluated the aptitude of the code Neptune_CFD to reproduce the incidence of a structure topped by vanes on a boiling layer, within the framework of the Neptune project. The objective was to reproduce the main effects of the spacer grids. The turbulence of the liquid phase was modeled by a first-orderK-εmodel. We show in this paper that this model is unable to describe the turbulence of rotating flows, in accordance with the theory. The objective of this paper is to improve the turbulence modeling of the liquid phase by a second turbulence model based on aRij-εapproach. Results obtained on typical single-phase cases highlight the improvement of the prediction for all computed values. We tested the turbulence modelRij-εimplemented in the code versus typical adiabatic two-phase flow experiments. We check that the simulations with the Reynolds stress transport model (RSTM) give satisfactory results in a simple geometry as compared to aK-εmodel: this point is crucial before calculating rod bundle geometries where theK-εmodel may fail.

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