Recent content by sanson

Let’s say ##u## is the velocity vector and the partial derivative are spatial derivative of the velocity vector. I am wondering if I am getting a single number, a vector or a tensor.

Dear Perok, Thanks for both, the correction and the explanation. I imagine the same solution but I am not always so sure with the index notation applied to partial derivatives... to further clarify, that expression gives always an scalar? Or there is not enough information to affirm that?

Hi all, I am having some problems expanding an equation with index notation. The equation is the following: $$\frac {\partial{u_i}} {dx_j}\frac {\partial{u_i}} {dx_j} $$ I considering if summation index is done over i=1,2,3 and then over j=1,2,3 or ifit does not apply. Any hint on this would...