[A Small Question about the Equations of LINCOM]

Dear Morten,

Thanks for your kind answer. I will think a little more about it. Thanks also for the later reference, which I had not seen. I have just downloaded it and will read it with interest.

Cheers, Paul.

[A Small Question about the Equations of LINCOM]

Hi, I am new to CFD, and trying to understand. I am reading the nice review of the mathematics behind LINCOM at: RIS_R_900.pdf. I take Eqs. (8) and (9) with the substitution (10), and we clearly have 4 equations in 4 unknowns. Very good. We expand according to (11) and (12). Here I understand that we have doubled the number of unknowns to 8. But some magic (presumably Reynolds averaging) gives the extra equations (13)-(15), which seem to be 5 equations, probably with some redundancy. So let us say 4, and we still have enough constrains. Still good.

At this point, however, I notice that Eq. (14) looks like a typing error. Since the right hand side is a vector zero, I have to assume that on the LHS here, we mean Curl(\bold v), (the curl symbol has been omitted). But I am anyway mystified at this point, since if I look to Eq. (2), I find that

\bold V = (cos th, sin th, 0) (U*0/kappa)ln(z/z_0)

Now, it seems to me that the curl of this "background flow" is not zero at all. In fact, it is a rotational flow.

So, is the notation \bold V intended to mean different things in eqs. (2) and (14), or is Eq.(14) meant to mean something other than curl (\bold V)=\bold 0?

Thanks in advance for any clarification.

Best Wishes,

Paul Harrison.