Low Reynolds Number Experimental Studies on Flat Plates

2014 ◽  
Author(s):  
Robbie J. Stevens ◽  
Holger Babinsky
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Experimental Studies ◽  
Flat Plates ◽  
Low Reynolds

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.

Low Reynolds number fully developed two-dimensional turbulent channel flow with system rotation

1996 ◽  
Vol 315 ◽  
pp. 1-29 ◽  
Author(s):  
Koichi Nakabayashi ◽  
Osami Kitoh
Keyword(s):  
Reynolds Number ◽  
Skin Friction ◽  
Coriolis Force ◽  
Low Reynolds Number ◽  
Experimental Studies ◽  
Velocity Profiles ◽  
Friction Coefficients ◽  
Number Range ◽  
System Rotation ◽  
Low Reynolds

Theoretical and experimental studies have been performed on fully developed twodimensional turbulent channel flows in the low Reynolds number range that are subjected to system rotation. The turbulence is affected by the Coriolis force and the low Reynolds number simultaneously. Using dimensional analysis, the relevant parameters of this flow are found to be Reynolds number Re* = u*D/v (u* is the friction velocity, D the channel half-width) and Ωv/u2* (Ω is the angular velocity of the channel) for the inner region, and Re* and ΩD/u* for the core region. Employing these parameters, changes of skin friction coefficients and velocity profiles compared to nonrotating flow can be reasonably well understood. A Coriolis region where the Coriolis force effect predominates is shown to exist in addition to conventional regions such as viscous and buffer regions. A flow regime diagram that indicates ranges of these regions as a function of Re* and |Ω|v/u2* is given from which the overall flow structure in a rotating channel can be obtained.Experiments have been made in the range of 56 ≤ Re* ≤ 310 and -0.0057 ≤ Ωv/u2* ≤ 0.0030 (these values correspond to Re = 2UmD/v from 1700 to 10000 and rotation number R0 = 2|Ω|D/Um up to 0.055; Um is bulk mean velocity). The characteristic features of velocity profiles and the variation of skin friction coefficients are discussed in relation to the theoretical considerations.

Low Reynolds Number Flow Between Interrupted Flat Plates

1983 ◽  
Vol 105 (1) ◽  
pp. 166-171 ◽  
Author(s):  
R. E. Roadman ◽  
R. I. Loehrke
Keyword(s):  
Reynolds Number ◽  
Critical Velocity ◽  
Low Reynolds Number ◽  
Separation Distance ◽  
Flat Plates ◽  
Reynolds Number Flow ◽  
Plate Length ◽  
Level Data ◽  
Number Flow ◽  
Low Reynolds

The flow between pairs of flat plates was studied experimentally to gain insight into the operation of compact heat exchangers with interrupted surfaces. The plates were tested at low Reynolds number in both water and air streams. The investigation focused on the region of transition from steady to unsteady laminar flow between plates. A critical velocity was determined at which periodic oscillations were first observed. This velocity depends strongly on the thickness of the plates, t, plate length, L, and plate separation distance and weakly on flow disturbance level. Data for a range of geometries, 4 ≤ L/t ≤ 159, are correlated using plate wake width as a single plate length scale. The downstream plate was found to have a pronounced upstream influence on the critical velocity. In a low-disturbance-level stream the critical velocity may be lower than that required to produce detectable oscillations at the same point in the upstream plate wake in absence of the second plate. This feedback effect may be responsible for the relative insensitivity of the results to the turbulence level in the free stream.

scholarly journals Compressibility effects on flat-plates with serrated leading-edges at a low Reynolds number

2017 ◽  
Vol 58 (11) ◽  
Author(s):  
Étienne Mangeol ◽  
Daichi Ishiwaki ◽  
Nicolas Wallisky ◽  
Keisuke Asai ◽  
Taku Nonomura
Keyword(s):  
Reynolds Number ◽  
Low Reynolds Number ◽  
Flat Plates ◽  
Leading Edges ◽  
Low Reynolds ◽  
Compressibility Effects

scholarly journals Experimental investigation of a low Reynolds number flame jet impinging flat plates

2020 ◽  
Vol 156 ◽  
pp. 119856 ◽  
Author(s):  
Eliot Schuhler ◽  
Bertrand Lecordier ◽  
Jérôme Yon ◽  
Gilles Godard ◽  
Alexis Coppalle
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Low Reynolds Number ◽  
Flat Plates ◽  
Low Reynolds
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