- #1
sa1988
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Homework Statement
Find acceleration for a general point (x, y) at time t, in the velocity field u = (y, t-x)
Homework Equations
Du/Dt = ∂u/∂t + (u⋅∇)u
The Attempt at a Solution
∂u/∂t = (0, 1)
(u⋅∇)u = [(y, t-x)⋅(∂/∂x, ∂/∂y)](y, t-x)
= (0 + 0)(y, t-x) = (0, 0)
Thus Du/Dt = ∂u/∂t + (u⋅∇)u = (0, 1) + (0, 0)
= (0, 1)
It seems correct but my lecturer has given a different example, for a different problem, in which he draws out the entire process (presumably for the sake of letting students follow every tiny step) but I think there are typos in his work and it's really confusing things for me. So I've stuck with what I believe to be correct, but would like to run it by you guys to see if things are all ok.
Thanks!
For reference, my lecturer's example is here - http://www1.maths.leeds.ac.uk/~kersale/2620/Examples/sol1.pdf - The part on the final page.
It looks like he's written ∂/∂x in far too many places...?