Reynolds number of a flow around a car

Rafaelle55 · February 14, 2019, 10:28

Hi,

I struggle choosing between the length, the height, and the width of the car to calculate the Reynolds number of a flow around a car. Is the direction of the flow indicates that we should take the length of the car?
I tried to find papers on flow around cars and it seems that sometimes the width is used, sometimes the height is used, sometimes the length is used; I'm then a bit confused.

Sincerely

LuckyTran · February 14, 2019, 10:35

There are infinite Reynold number variants. There is even a Reynolds number based on font size. What you are going to do with the Reynolds number is what determines which one you use. Why do you need Reynolds number?

February 14, 2019, 10:28	Reynolds number of a flow around a car	#1
Rafaelle55 New Member Rafaelle Join Date: Dec 2018 Posts: 3 Rep Power: 7	Hi, I struggle choosing between the length, the height, and the width of the car to calculate the Reynolds number of a flow around a car. Is the direction of the flow indicates that we should take the length of the car? I tried to find papers on flow around cars and it seems that sometimes the width is used, sometimes the height is used, sometimes the length is used; I'm then a bit confused. Sincerely

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February 14, 2019, 10:35		#2
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,668 Rep Power: 65	There are infinite Reynold number variants. There is even a Reynolds number based on font size. What you are going to do with the Reynolds number is what determines which one you use. Why do you need Reynolds number?