In this paper (High Reynolds Number Oscillations of
a Circular Cylinder) they mentioning body strouhal number ... and strouhal number. i didn't get what they are concluded they are taking the angular freq and angular velocity in this paper. I attached the paper and its base paper please clarifiy me the doubts regarding body strouhal. Looking forward.
Dear Rajasekarababu,
What there is to know The Strouhal number (St) is a dimensionless number describing oscillating flow mechanisms.
Physically it represents the ratio of advection time and time characteristic of the unsteadiness. If St is less than unity, this means that the flow is quasi-stationary.
For a circular section cylinder this number remains, in a wide range of Reynolds, approximately constant and equal to 0.2. In other words, the vortices secondment period is proportional to the speed.
The value of St undergoes a sudden change to a critical Re = 3.5x105. Indeed for Re, St passes from 0.2 to 0.45. St custody great values for a large range of values of Re in the supercritical regime before decreasing by increasing Re.
We can explain the important values taken by St in the supercritical regime as follows: In this regime the boundary layers on both sides of the cylinder are turbulent at split which implies a movement of the latter downstream.
With my best regards
Prof. Bachir ACHOUR
Dear Rajasekarababu,
I join you in attached figures that summarize my comment.
With my best regards
prof. Bachir ACHOUR
Sir Thank you... I found some answer in that file which you attached... And I attached a image they are introduced a word body strouhal.. And strouhal please take a look that image and explain me sir Thank you
Dear Rajasekarababu,
The formula corresponds to the definition of the Strouhal number of a body.
fb is the transmission frequency of the vortices, d is the diameter of the body and U is the velocity of the flow. But, I do know what bands it is. Surely there is an explanatory graph.
With my best regards
Prof. Bachir ACHOUR
Dear Rajasekarababu,
In 1878, studying the notes issued by a taut wire subject to wind, Czech physicist Vincent Strouhal was the first to notice the relationship between the frequency of the sound and the wire diameter divided by the speed of the wind.
This relationship is expressed by the following formula:
St = f D / V
with:
f - swirls transmission frequency;
D - characteristic length (diameter of the wire in the experiments of Strouhal);
V - the speed of undisturbed flow.
With my best regards
Prof. Bachir ACHOUR
Dear Rajasekarababu,
I stand at your disposal.
With my best regards
Prof. Bachir ACHOUR