[Bharatt]

Hello,

I am simulating unsteady laminar flow over an airfoil for the Reynolds number 70,000 for different AoA. the reason why i am performing this is to check whether the airfoil stall's or not.i am getting convergence in the solution, but my main concerns are coefficients(drag, lift and moment). HERE, i am enabling "data sampling for time statistics" option (DSTS) under iterate window, which according to the description, will give the root mean square of the coefficients (now, i assume that it will converge after sometime and becomes constant, which i assume a constant value for further "n" number of iterations).but that's not the case, even i select the DSTS my coefficient plots are still oscillating, since my main aim is to compare the coefficients with different AoA's). i am posting a plot for Cl for the reference. one more thing, i am using very fine mesh.

PLEASE HELP .

Bharat

[NormalVector]

What does the flow field look like? Is that oscillating? There may be some vortex shedding.

[Bharatt]

Hey,

Thanks for your kind attention .

Certainly, there is vortex shedding in the flow field. here i post you one picture. please have a look.

[Far]

you want to find out the fluctuating and mean coefficients?

[Bharatt]

Sir,

I am glad that you've replied.

My main concern is to get the mean coefficient value(lift, drag and moment for unsteady laminar flow), which i can compare with turbulent flow.

bharat

[micro11sl]

Originally Posted by Bharatt

Sir,

I am glad that you've replied.

My main concern is to get the mean coefficient value(lift, drag and moment for unsteady laminar flow), which i can compare with turbulent flow.

bharat

I suppose you have solved the problem already. One easy way is to copy periodic Cl output values to Excel and get a mean value from there, assuming constant time steps.