DSMC Calculation of Vortex Shedding behind a Flat Plate with a New Intermolecular Collision Scheme

2005 ◽  
Author(s):  
M. Usami
Keyword(s):  
Flat Plate ◽  
Vortex Shedding ◽  
Intermolecular Collision

Vortex Shedding Analysis in the Wake of a Flat Plate at Low Incidence and Low Reynolds Number

2021 ◽  
Author(s):  
Bastav Borah ◽  
Anand Verma ◽  
Vinayak Kulkarni ◽  
Ujjwal K. Saha
Keyword(s):  
Reynolds Number ◽  
Velocity Field ◽  
Flat Plate ◽  
Vortex Shedding ◽  
Low Reynolds Number ◽  
General Tendency ◽  
Flat Plates ◽  
Trailing Edge ◽  
Low Reynolds ◽  
Low Incidence

Abstract Vortex shedding phenomenon leads to a number of different features such as flow induced vibrations, fluid mixing, heat transfer and noise generation. With respect to aerodynamic application, the intensity of vortex shedding and the size of vortices play an essential role in the generation of lift and drag forces on an airfoil. The flat plates are known to have a better lift-to-drag ratio than conventional airfoils at low Reynolds number (Re). A better understanding of the shedding behavior will help aerodynamicists to implement flat plates at low Re specific applications such as fixed-wing micro air vehicle (MAV). In the present study, the shedding of vortices in the wake of a flat plate at low incidence has been studied experimentally in a low-speed subsonic wind tunnel at a Re of 5 × 104. The velocity field in the wake of the plate is measured using a hot wire anemometer. These measurements are taken at specific points in the wake across the flow direction and above the suction side of the flat plate. The velocity field is found to oscillate with one dominant frequency of fluctuation. The Strouhal number (St), calculated from this frequency, is computed for different angles of attack (AoA). The shedding frequency of vortices from the trailing edge of the flat plate has a general tendency to increase with AoA. In this paper, the generation and subsequent shedding of leading edge and trailing edge vortices in the wake of a flat plate are discussed.

Feedback control of vortex shedding from an inclined flat plate

2010 ◽  
Vol 25 (1-4) ◽  
pp. 221-232 ◽  
Author(s):  
Won Tae Joe ◽  
Tim Colonius ◽  
Douglas G. MacMynowski
Keyword(s):  
Feedback Control ◽  
Flat Plate ◽  
Vortex Shedding

Noise Radiated by Flow Impingement on a Flat Plate Using DNS with a Virtual Boundary Method

2005 ◽  
Vol 4 (1-2) ◽  
pp. 117-134 ◽  
Author(s):  
F. Margnat ◽  
V. Morinière ◽  
Y. Gervais
Keyword(s):  
Flat Plate ◽  
Vortex Shedding ◽  
Leading Edge ◽  
Uniform Grid ◽  
Far Field ◽  
Sound Emission ◽  
Maximum Value ◽  
Boundary Method ◽  
Hydrodynamic Field ◽  
Virtual Boundary

Uniform flow impinging on the rectangular leading edge of a flat plate is simulated using an incompressible, two-dimensional direct numerical simulation with uniform grid, the solid surface being modelled by the virtual boundary method previously developed by Goldstein et al. Access is given to the hydrodynamic field at a Reynolds number of 500, which shows the separation at the edge, the development of a double recirculating bubble, a periodic vortex-shedding, and the generation of a boundary layer profile after the re-attachment point. Curle's analogy is then applied to evaluate the sound emission in the far field. Results are given in terms of far field pressure levels directivity and pressure spectra associated with surfacic or volumic sources. The emission from the surfacic sources reaches its maximum value in the direction perpendicular to the plate and acoustic frequencies tend to follow the main wall pressure frequencies of the flow, while the emission from the volumic sources exhibits a shear noise behaviour and acoustic frequencies seem to be the double of the main velocity frequencies.

DSMC Calculation for Vortex Shedding behind an Inclined Flat Plate

2003 ◽  
Vol 2003.52 (0) ◽  
pp. 1-2
Author(s):  
Keisuke MIZUGUCHI ◽  
Masaru USAMI
Keyword(s):  
Flat Plate ◽  
Vortex Shedding

scholarly journals Numerical Investigation on the Effects of Vortex Shedding on Boundary Layer Unsteadiness

1970 ◽  
Vol 37 ◽  
pp. 33-39
Author(s):  
ABM Toufique Hasan ◽  
Dipak Kanti Das
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Finite Element ◽  
Flow Field ◽  
Flat Plate ◽  
Vortex Shedding ◽  
Stokes Equations ◽  
Number Range ◽  
Rotating Speed ◽  
Rotating Circular Cylinder

The interaction between an initially laminar boundary layer developed spatially on a flat plate under the influence of vortex shedding induced from a rotating circular cylinder has been simulated numerically. The rotational speed of the cylinder is varied to generate the vortex shedding of different intensities. Also the flat plate is kept at different positions from the cylinder. Due to asymmetry in the flow field, the present problem is governed by unsteady Navier-Stokes equations which are simulated numerically by finite element method. Computations are carried out for low Reynolds number range up to 1000. Instantaneous development of the flow field, unsteady boundary layer integral parameters, and wall skin friction are presented on different streamwise locations over the plate. From the computation, it is observed that the vortex shedding substantially affects the boundary layer development. The disturbed displacement and momentum thicknesses of the plate increase up to 1.6 times and 2.6 times of the undisturbed flow, respectively. Also the plate shape factor approaches a value of 1.5 which is typical for turbulent flow. This interaction strongly depends on the rotating speed of the cylinder, the relative positions of the cylinder and the plate and also on Reynolds number of the flow. Keywords: Vortex shedding, finite element, boundary layer, wall skin friction.doi:10.3329/jme.v37i0.817Journal of Mechanical Engineering Vol.37 June 2007, pp.33-39

A contribution to an inviscid vortex-shedding model for an inclined flat plate in uniform flow

1977 ◽  
Vol 82 (2) ◽  
pp. 223-240 ◽  
Author(s):  
Masaru Kiya ◽  
Mikio Arie
Keyword(s):  
Flat Plate ◽  
Vortex Shedding ◽  
Separated Flow ◽  
Flow Patterns ◽  
Shear Layers ◽  
Visualization Technique ◽  
Time Intervals ◽  
Discrete Vortex ◽  
Kutta Condition ◽  
Vorticity Transport

Unsteady separated flow behind an inclined flat plate is numerically studied through the use of the discrete-vortex approximation, in which the shear layers emanating from the edges of the plate are represented by an array of discrete vortices introduced into the flow field at appropriate time intervals at some fixed points near the edges of the plate. The strengths of the nascent vortices are chosen so as to satisfy the Kutta condition at the edges of the plate. Numerical calculations are performed for a plate at 60° incidence impulsively started from rest in an otherwise stationary incompressible fluid, by systematically changing the distance between the location of the nascent vortices and the edges of the plate. The temporal changes in the drag force, the rate of vorticity transport at both edges of the plate and the velocity of the separated shear layers are given together with the flow patterns behind the plate on the basis of this model. The results of the computation show that the vortex street behind the plate inclines as a whole towards the direction of the time-averaged lift force exerted on the plate. It is also predicted from the calculations that the vortex shedding at one edge of the plate will not occur at the mid-interval of the successive vortex shedding at the other edge. The predicted flow patterns are not inconsistent with a few experimental observations based on the flow-visualization technique.

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