Ground Viscous Effect on Aerodynamics of a Compound Wing with Different Reynolds Number

2013 ◽  
Vol 465-466 ◽  
pp. 379-383
Author(s):  
Saeed Jamei ◽  
Agoes Priyanto ◽  
Adi Maimun ◽  
Mohammad Mobassher Tofa ◽  
Nor Azwadi ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Boundary Layers ◽  
Numerical Study ◽  
Ground Effect ◽  
Good Method ◽  
Aerodynamic Coefficients ◽  
Moment Coefficient ◽  
Numerical Result ◽  
Computational Fluid Dynamics Cfd ◽  
Lift And Drag

The fly of wing-in-ground effect (WIG) crafts can be affected by ground boundary layers. In this study, the effect of ground viscous on aerodynamic coefficients of a compound wing of WIG craft was numerically investigated. Computational fluid dynamics (CFD) was used for numerical study. The simulations were done respect to different ground clearance and Reynolds number. A realizable k-ε turbulent model was employed for the modelling flow field around the wing area. The numerical results of the compound wing for fixed ground validated with the experimental data. Aerodynamic coefficients of the compound wing were determined for fixed and moving ground. Accordingly, the numerical result presented that lift and drag coefficients and lift to drag ratio has been affected by ground boundary layers while moment coefficient and centre of pressure of compound wing had no more variation due to remove ground viscous. The effect of ground viscous on aerodynamics of the compound wing had a slight changes respect to Reynolds number. CFD can be employed as a good method to find the influence of ground viscous on aerodynamics of WIG crafts.

scholarly journals Numerical Study of Flow Characteristics Around Confined Cylinder using OpenFOAM

2018 ◽  
Vol 7 (4.35) ◽  
pp. 617
Author(s):  
P. Mathupriya ◽  
L. Chan ◽  
H. Hasini ◽  
A. Ooi
Keyword(s):  
Reynolds Number ◽  
Vortex Shedding ◽  
Numerical Study ◽  
Vortex Formation ◽  
Plane Channel ◽  
Flow Characteristics ◽  
Strong Interactions ◽  
Two Dimensional ◽  
Computational Fluid Dynamics Cfd ◽  
Shedding Frequency

The numerical study of the flow over a two-dimensional cylinder which is symmetrically confined in a plane channel is presented to study the characteristics of vortex shedding. The numerical model has been established using direct numerical simulation (DNS) based on the open source computational fluid dynamics (CFD) code named OpenFOAM. In the present study, the flow fields have been computed at blockage ratio, β of 0.5 and at Reynolds number, Re of 200 and 300. Two-dimensional simulations investigated on the effects of Reynolds number based on the vortex formation and shedding frequency. It was observed that the presence of two distinct shedding frequencies appear at higher Reynolds number due to the confinement effects where there is strong interactions between boundary layer, shear layer and the wake of the cylinder. The range of simulations conducted here has shown to produce results consistent with that available in the open literature. Therefore, OpenFOAM is found to be able to accurately capture the complex physics of the flow.

Aerodynamic Behavior of a Compound Wing Configuration in Ground Effect

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Saeed Jamei ◽  
Adi Maimun ◽  
Shuhaimi Mansor ◽  
Agoes Priyanto ◽  
Nor Azwadi ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Ground Effect ◽  
Tip Vortex ◽  
Aerodynamic Coefficients ◽  
Ground Clearance ◽  
Reverse Taper ◽  
Current Experimental Data ◽  
Computational Fluid Dynamics Cfd ◽  
Ram Effect ◽  
Wing In Ground Effect

The aerodynamic coefficients of wing in ground effect can be affected with its design which can be the main parameter for efficiency of wing-in-ground effect craft. In this study, the aerodynamic coefficients of a compound wing were numerically determined in ground effect. The compound wing was divided into three parts with one rectangular wing in the middle and two reverse taper wings with an anhedral angle at the sides. An NACA6409 airfoil was employed as a section of wings. Three dimensional (3D) computational fluid dynamics (CFD) was applied as a numerical scheme. A realizable k-ε turbulent model was used for simulation the turbulent flow around the wing surfaces. For validation purpose, the numerical results of a compound wing with aspect ratio 1.25, at ground clearance of 0.15 and different angles of attack were compared with the current experimental data. Then, the aerodynamic coefficients of the compound wings were computed at various ground clearances and angle of attack of 4°. According to pressure and velocity distribution of air around wing surfaces, ground clearance had considerable effects on ram effect pressure and tip vortex of the compound wing, and aerodynamic coefficients of the compound wing had some improvements as compared with the rectangular wing.

Miniature gas turbines: Numerical study of the effects of heat transfer and Reynolds number on the performance of an axial compressor

2014 ◽  
Vol 03 (02) ◽  
pp. 1450008 ◽  
Author(s):  
Junting Xiang ◽  
Jörg Uwe Schlüter ◽  
Fei Duan
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Gas Turbines ◽  
Numerical Study ◽  
Axial Compressor ◽  
Thermal Conditions ◽  
Wall Heat Transfer ◽  
Viscous Effects ◽  
Computational Fluid Dynamics Cfd ◽  
Compressor Performance

In the present work, we focus on computational investigations of the Reynolds number effect and the wall heat transfer on the performance of axial compressor during its miniaturization. The NASA stage 35 compressor is selected as the configuration in this study and computational fluid dynamics (CFD) is used to carry out the miniaturization process and simulations. We perform parameter studies on the effect of Reynolds number and wall thermal conditions. Our results indicate a decrease of efficiency, if the compressor is miniaturized based on its original geometry due to the increase of viscous effects. The increased heat transfer through wall has only a small effect and will actually benefit compressor performance based on our study.

scholarly journals Numerical Study of the Effect of Wing Position on Autonomous Underwater Glider

2020 ◽  
Vol 70 (2) ◽  
pp. 214-220
Author(s):  
R.V. Shashank Shankar ◽  
Rajagopalan Vijayakumar
Keyword(s):  
Numerical Study ◽  
Reynolds Numbers ◽  
Hydrodynamic Characteristics ◽  
Underwater Glider ◽  
Low Reynolds Numbers ◽  
Underwater Gliders ◽  
Turning Motion ◽  
Computational Fluid Dynamics Cfd ◽  
Lift And Drag ◽  
Autonomous Underwater Glider

 Autonomous underwater gliders are a class of underwater vehicles that transit without the help of a conventional propeller. The vehicle uses a buoyancy engine to vary its buoyancy and with the help of the wings attached executes its motion. The hydrodynamic characteristics of the vehicle affect the longitudinal and turning motion. This paper discusses the effect of the wing’s position on the vehicle’s lift and drag characteristics. Computational fluid dynamics (CFD) tool is used to estimate the lift, drag, and pitching moment coefficients of the vehicle. The numerical methodology is validated using flow over NACA0012 wing results for low Reynolds numbers, and the results of CFD are discussed for possible application in estimation of glider motion.

Numerical Study of Aerodynamic Forces of Two Airfoils in Tandem Configuration at Low Reynolds Number

2021 ◽  
Author(s):  
N. Hosseini ◽  
M. Tadjfar ◽  
A. Abba
Keyword(s):  
Reynolds Number ◽  
Numerical Study ◽  
Low Reynolds Number ◽  
Aerodynamic Forces ◽  
Tandem Configuration ◽  
Pitching Airfoil ◽  
Reduced Frequency ◽  
Low Reynolds ◽  
Lift And Drag ◽  
Two Parameters

Abstract For a tandem airfoil configuration, an airfoil is placed in the wake of an upstream airfoil. This interaction affects the aerodynamic forces of the airfoils, especially the downstream one. In the present study a tandem configuration consists of an upstream pitching airfoil and a downstream stationary airfoil is investigated. This study aims to investigate the role of reduced frequency and pitch amplitude of the upstream airfoil’s motion on lift and drag coefficients of two airfoils. These two parameters play an important role in the formation of vortices. The investigation is done for Selig-Donovan 7003 (SD7003) airfoils at low Reynolds number of 30,000 using a computational fluid dynamics. Incompressible URANS equations were employed for solving the flow field. It was found that for a fixed reduced frequency of 0.5 thrust is produced on the hindfoil for a part of cycle for different pitch amplitudes from light to deep stall while for a fixed pitch amplitude at different reduced frequencies high level of thrust or drag can be produced. The reason is related to the type and intensity of vortex-blade interaction.

Vortex Shedding From a Square Cylinder With Ground Effect

2003 ◽  
Author(s):  
S. Bhattacharyya ◽  
D. K. Maiti
Keyword(s):  
Reynolds Number ◽  
Vortex Shedding ◽  
Stokes Equations ◽  
Numerical Study ◽  
Ground Effect ◽  
Staggered Grid ◽  
Navier Stokes ◽  
Square Cylinder ◽  
Navier Stokes Equations ◽  
Cylinder Length

Numerical study on the wake behind a square cylinder placed parallel to a wall has been made. Flow has been investigated in the laminar Reynolds number (based on the cylinder length) range. We have studied the flow field for different values of the non-dimensional gap length between cylinder and the wall. The case when the cylinder is placed on the wall has also been considered. The governing unsteady Navier-Stokes equations are discretised through the finite volume method on staggered grid system. A SIMPLER type of algorithm has been used to compute the discretised equations iteratively. Vortex shedding has been found to be influenced by the wall. Vortex shedding suppression occurs beyond a critical value of the gap length. Due to the shear, the drag experienced by the cylinder is found to increase with the reduction of gap length. The flow is found to be steady when the cylinder is placed on the wall at a range of Reynolds number.

Lateral-Directional Aerodynamics of a Canard Guided Spin Stabilized Projectile at Supersonic Velocity

2011 ◽  
Vol 110-116 ◽  
pp. 4343-4350 ◽  
Author(s):  
Xiu Ling Ji ◽  
Hai Peng Wang ◽  
Shi Ming Zeng ◽  
Chen Yang Jia
Keyword(s):  
Computational Study ◽  
Cfd Modeling ◽  
Aerodynamic Coefficients ◽  
Force Coefficient ◽  
Modeling And Analysis ◽  
Moment Coefficient ◽  
Computational Fluid Dynamics Cfd ◽  
Spinning Projectile ◽  
Yaw Moment ◽  
Side Force Coefficient

A computational study performed for a canard guided spin stabilized projectile using finite volume TVD schemes is described in this paper. Computational Fluid Dynamics (CFD) modeling and analysis of the spinning projectile with fixed canard are conducted to determine the lateral-directional aerodynamic coefficients at three supersonic speeds and various angles of attack. The analyses provide a detailed understanding of the effects of canard with different circumferential position on lateral-directional aerodynamic coefficients, and the results show that side force coefficient and yaw moment coefficient vary periodically with the circumferential position angles of canard.

Instabilities in the flow between co- and counter-rotating disks

2002 ◽  
Vol 473 ◽  
pp. 1-21 ◽  
Author(s):  
G. GAUTHIER ◽  
P. GONDRET ◽  
F. MOISY ◽  
M. RABAUD
Keyword(s):  
Reynolds Number ◽  
Boundary Layers ◽  
Numerical Study ◽  
Cell Structure ◽  
Rotating Cylinder ◽  
Basic Flow ◽  
Rotating Disks ◽  
Recirculation Flow ◽  
Phase Velocities ◽  
Counter Rotation

The flow between two rotating disks (radius to heigh ratio of 20.9), enclosed by a rotating cylinder, is investigated experimentally in the cases of both co- and counter-rotation. This flow gives rise to a large gallery of instability patterns. A regime diagram of these patterns is presented in the (Reb,Ret)-plane, where Reb,t is the Reynolds number associated with each disk. The co-rotation case and the weak counter-rotation case are very similar to the rotor–stator case, both for the basic flow and the instability patterns: the basic flow consists of two boundary layers near each disk and the instability patterns are the axisymmetric vortices and the positive spirals described in the rotor–stator experiments of Gauthier, Gondret & Rabaud (1999), Schouveiler, Le Gal & Chauve (2001), and the numerical study of Serre, Crespo del Arco & Bontoux (2001). The counter-rotation case with higher rotation ratio is more complex: above a given rotation ratio, the recirculation flow becomes organized into a two-cell structure with the appearance of a stagnation circle on the slower disk. A new kind of instability pattern is observed, called negative spirals. Measurements of the main characteristics of this pattern are presented, including growth times, critical modes and phase velocities.

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