Calculation of w component
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Hi Guys,
I currently preparing a paper on secondary currents and am having some difficulty with some data calculations. The data I have has been measured using LDA equipment in a rectangular flume. I have accurate data for u and v components but need to calculate the w component mathematically. I have been told that this is possible using the equation shown in the attachment. Apparently the differential is calculated using a standard fivepoint centerdifference operator, and the integral was computed from the trapezium rule assuming that the crossstream velocity at the wall was zero. I hope that someone on here can make sense of this as it is really doing my head in. Thanks for your help! 
if you have a 3D Case, the flow being subject to the divergencefree contraint, then:
dW/dz=(dU/dx + dV/dy) thus, if you have U and V fields you can integrate anc compute W 
Yeah you've hit the nail on the head!
I am just not sure how to perform the maths. The conditions are such that there is no variation is streamwise, u, velocity, so that term can be removed. The v data I have is in the following form (the top row is the z locations and the left column are the y locations): v 14.3203 27.88824 41.45621 55.22419 68.59216 8.5 0.000597 0.001682 0.003992 0.010048 0.008707 10 0.000297 0.00017 0.005296 0.010319 0.009262 12 0.000935 0.00093 0.004421 0.009234 0.010913 15 0.000514 0.00107 0.004239 0.010468 0.01063 18 0.000483 0.00249 0.004134 0.011069 0.011067 20 0.000898 0.00229 0.003639 0.011235 0.012193 If you could help me out with the calculation that would be amazing! Thanks 
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You make it sound so easy!
If you could dumb this down and give me an example for 1 of the points I will be that stoked I'll do a seated backflip. 
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I'll read up and try to figure it out.
Thanks a bunch for your help! 
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