Recent content by j_phillips

That was easy! Thanks much.

I have a similar question, but here I'm just interested in the derivation of the Stokes equation (Material Equation, etc): Where a=dV/dt and V is a vector of d/dt(u,v,w) (i,j,k are respective here). But my fundamental question is why u, v, and w would be functions of (x,y,z,t)? I understand t...

Thanks! Much appreciated!

I appreciate the welcome! This would be steady-state so the right side of the equation would go to zero. If k=x, then d/dx(k) would equal a constant K, but then there is t d/dx*T term which would be unaccounted for? Instead of a constant (K), let's say k(x,T)=100+cos(2x) for 0<x<(pi/2) (I'm...

I'm interested in modeling a system where the material varies along its length, thus the conductivity coefficient would be a function of both T, and x. k(T,x). For starters, if I assume negligible change w.r.t T, then he heat diffusion equation would be d/dt(k(x)dT/dx)=0. Correct? What if k just...

I was thinking about this today and looked up a bit about the history of mass measurement. Obviously it is still defined by a physical object (an ingot of some alloy). My question is more toward defining it another way. Why not use Kepler's law's aka. gravity? If we can define Force as a...