[AeroSonic]

Dear All,

I am doing literature review about low Reynolds number flows, and while reading, I found some research papers speaks about Tollmien–Schlichting wave and some speaks about Kelvin-Helmholtz instability.

Is there any relation between them?

If a very low Reynolds number flow ( 4000 for example ) is being simulated over airfoil, probably a laminar separation bubble will take place and a turbulent wake will exist. do I have to include a turbulence model ?

Thanks in advance.

[AeroSonic]

Can anyone help, please

[FMDenaro]

At such a Re the flow would be laminar along the airfoil. I doubt you have a separation bubble

[AeroSonic]

Originally Posted by FMDenaro

At such a Re the flow would be laminar along the airfoil. I doubt you have a separation bubble

when I increase the angle of attack, the flow at the suction side start to form the laminar separation bubble.

how do I know decide the type of the instability, is it K-H instability of T-S instability

[FMDenaro]

Originally Posted by AeroSonic

when I increase the angle of attack, the flow at the suction side start to form the laminar separation bubble.

how do I know decide the type of the instability, is it K-H instability of T-S instability

What you are talking about at high angle of attack is a geometria separation, nothing to do with the classic fluid dynamics instability

[AeroSonic]

Originally Posted by FMDenaro

What you are talking about at high angle of attack is a geometria separation, nothing to do with the classic fluid dynamics instability

I already tried simulating 0012 airfoil at different Reynolds number such as 4000,5000,6000 and an angle of attack of 5 and 6. I tried a flow control method and different laminar separation bubble were bursting. Also, a laminar separation bubble was formed in the rigid case.

[AeroSonic]

Can anyone help, please