Numerical Investigations of Aerodynamic Forces on 2-D Square Lattice Tower Section Using Two-Equation Turbulence Models

Purpose The purpose of this paper is to describe experimental and numerical investigations focussed on the shock wave modification induced by a dc glow discharge. The model is a flat plate in a rarefied Mach 2 air flow, equipped with a plasma actuator composed of two electrodes. The natural flow without actuation exhibits a shock wave with a hyperbolic shape. When the discharge is on, the shock wave shape remains hyperbolic but the shock wave is pushed forward, leading to an increase in the shock wave angle. In order to discriminate thermal effects from purely plasma ones, the plasma actuator is then replaced by an heating element. Design/methodology/approach The experimental study is carried out with the super/hypersonic wind tunnel MARHy located at the ICARE Laboratory in Orléans. The experimental configuration with the heating element is simulated with a code using the 2D full compressible Navier-Stokes equations adapted for the rarefied conditions. Findings For heating element temperatures equal to the flat plate wall surface ones with the discharge on, experimental and numerical investigations showed that the shock wave angle was lower with the heating element, only 50 percent of the values got with the plasma actuator, meaning that purely plasma effects must also be considered to fully explain the flow modifications observed. The results obtained with the numerical simulations are then used to calculate the aerodynamic forces, i.e. the drag and the lift. These numerical results are then extrapolated to the plasma actuator case and it was found that the drag coefficient rises up to 13 percent when the plasma actuator is used, compared to only 5 percent with the heating element. Originality/value This paper matters in the topic of atmospheric entries where flow control, heat management and aerodynamic forces are of huge importance.

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Experimental and Numerical Investigations on Turbine Airfoil Cooling Designs: Part I—An Investigation on Flow Features by Particle Image Velocimetry

Volume 4: Heat Transfer, Parts A and B ◽

10.1115/gt2008-50673 ◽

2008 ◽

Author(s):

J. H. Wang ◽

H. Z. Xu ◽

Y. L. Liu ◽

Z. N. Du ◽

S. J. Yang

Keyword(s):

Reynolds Number ◽

Particle Image ◽

Turbulence Models ◽

Velocity Fields ◽

Numerical Investigations ◽

Wall Film ◽

Image Velocimetry ◽

Flow Features ◽

Numerical Grid ◽

Double Wall

Experimental and numerical investigations are conducted to understand the features of the fluid dynamics within double-wall film-cooled configurations. Based on the similarity principle of the Reynolds number, a large-scale similar configuration made of transparent material is used as specimen, and the fluid velocity distributions over several typical cross sections within the specimen channel are captured by a particle image velocimetry (PIV) system. The experiments are carried out at a density ratio of fluid medium to tracer particle 1.05. The flow features are respectively calculated by different turbulence models and numerical grids. To confirm turbulence models and numerical grids, the numerical results are compared with the experimental data obtained by the PIV system. Through the comparisons, recommendations have been made with regard to the best model and numerical grid which best predict such velocity fields. The influences of inlet Reynolds numbers and the geometrical device of the double-wall film-cooled configurations on the features of flow field are numerically simulated by the recommended model and grid. The simulation results predicate that the flow features are mainly dominated by the geometrical device, the inlet Reynolds number can only result in a magnitude change of velocity fields, and this change is almost linear. This is the first part of the entire investigations on the double-wall film-cooled configurations, and the objective of this part is to confirm a suitable mathematical model and numerical grid for describing the flow features. In the next part, the overall heat transfer characteristics of these configurations will be studied.

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Turbulence-Model Comparison for Aerodynamic-Performance Prediction of a Typical Vertical-Axis Wind-Turbine Airfoil

Energies ◽

10.3390/en12030488 ◽

2019 ◽

Vol 12 (3) ◽

pp. 488 ◽

Cited By ~ 4

Author(s):

Andrés Meana-Fernández ◽

Jesús Fernández Oro ◽

Katia Argüelles Díaz ◽

Sandra Velarde-Suárez

Keyword(s):

Flow Field ◽

Turbulence Model ◽

Model Comparison ◽

Turbulence Models ◽

Vertical Axis ◽

Detached Eddy Simulation ◽

Vertical Axis Wind Turbine ◽

Aerodynamic Forces ◽

Navier Stokes Equation ◽

Rans Models

In this work, different turbulence models were applied to predict the performance of a DU-06-W-200 airfoil, a typical choice for vertical-axis wind turbines (VAWT). A compromise between simulation time and results was sought, focusing on the prediction of aerodynamic forces and the developed flow field. Reynolds-averaged Navier–Stokes equation (U-RANS) models and Scale-Resolving Simulations (SRS), such as Scale-Adaptive Simulation (SAS) and Detached Eddy Simulation (DES), were tested, with k − ω -based turbulence models providing the most accurate predictions of aerodynamic forces. A deeper study of three representative angles of attack (5 ° , 15 ° , and 25 ° ) showed that U-RANS models accurately predict aerodynamic forces with low computational costs. SRS modeling generates more realistic flow patterns: roll-up vortices, vortex packets, and stall cells have been identified, providing a richer unsteady flow-field description. The power spectrum density of velocity at 15 ° has confirmed a broadband spectrum in DES simulations, with a small peak at a Strouhal number of 0.486. Finally, indications regarding the selection of the turbulence model depending on the desired outcome (aerodynamic forces, airfoil flow field, or VAWT simulation) are provided, tending toward U-RANS models for the prediction of aerodynamic forces, and SRS models for flow-field study.

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Aero-Thermodynamic Aspects of Film Cooling in Regions of Separated Flow on the Pressure Side of a High-Lift HPT Blade

Volume 5: Turbo Expo 2004, Parts A and B ◽

10.1115/gt2004-54067 ◽

2004 ◽

Cited By ~ 2

Author(s):

Lars Homeier ◽

Ewald Lutum ◽

Erik Janke ◽

Frank Haselbach

Keyword(s):

Film Cooling ◽

High Speed ◽

Turbine Blades ◽

Turbulence Models ◽

Side Surface ◽

Pressure Side ◽

High Lift ◽

Numerical Investigations ◽

Coolant Injection ◽

Highly Loaded

Due to the ever increasing demand for cost-optimised designs, modern engine design concepts lead to more and more highly loaded HP turbine blades. In order to achieve the high lift required, turbine airfoils will have to cope with main flow diffusion up to separation both on suction and pressure side. Thus, for film cooled HP turbine blades and vanes, the possible aerodynamic and aero-thermal interaction of highly loaded blade rows and film cooling needs to be addressed. The first results to be presented from this ongoing work within the European 5th Frame-Work-Project AITEB jointly comprises experimental high-speed cascade wind-tunnel as well as numerical investigations with state-of-the-art 3D-RANS CFD. Steady and unsteady experimental results detailing the row characteristic of the highly-loaded T120 HP-turbine cascade set the stage for detailed numerical investigations with and without coolant injection from rows of holes on the pressure side surface as well as comparative numerical calculations with different codes and turbulence models. Despite the current focus of the experimental work on aerodynamic topics, the numerical results to be presented comprise thermodynamic investigations and detailed studies on optimised coolant injection geometries as well.

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Numerical investigations on aerodynamic forces of deformable foils in hovering motions

Physics of Fluids ◽

10.1063/1.4979212 ◽

2017 ◽

Vol 29 (4) ◽

pp. 041902 ◽

Cited By ~ 6

Author(s):

Xiaohui Su ◽

Zhen Yin ◽

Yuanwei Cao ◽

Yong Zhao

Keyword(s):

Aerodynamic Forces ◽

Numerical Investigations

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Drag Prediction on DLR-F6 Wing-Body Configuration

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.110-116.1506 ◽

2011 ◽

Vol 110-116 ◽

pp. 1506-1511

Author(s):

Qiu Ya Zheng ◽

San Yang Liu

Keyword(s):

Shock Wave ◽

Shear Stress ◽

Transport Model ◽

Turbulence Models ◽

Grid Refinement ◽

Friction Drag ◽

Aerodynamic Forces ◽

Pressure Distributions ◽

Shear Stress Transport Model ◽

Drag Prediction

This paper mainly investigate the accuracy of the computed drag on the DLR-F6 Wing-Body configuration, and analyze effect of grid and the turbulence models including the Spalart-Allmaras model, Wilcox’s k-ω model and Menter shear-stress transport model on aerodynamic forces for wing-body configuration. The computed results show that grid refinement has little effect on the pressure distributions, significant effect on drag. The turbulence models have certain effects on the pressure distributions, especially positions of the shock wave. They have obvious effects on drag, particularly friction drag. This study shows that performing the CFD calculation at the same angle-of-attack as experiment resulted in good comparisons with wing surface pressures.

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