Recent content by zekeman

"It now looks like a closed form solution is not possible, but maybe the expanded version will suffice if the terms converge rapidly." They did not so I'm back to square one, still stuck with getting the inverse transform of 1/s*e^(sF/(s+G) F, G constants Any other ideas would be most...

OK, took your advice and started to expand the fraction (s^2+D)/(Bs+C)=s/B+F/(s+G) The s/B term looks like the time delay of the function 1/s*e^[-x*(s^2+Ds)/(Bs+C)] so I now have e^-sx/B*1/s*e^[-x*(F)/(s+G)] I should get the inverse Laplace of 1/s*e^[-x*(F)/(s+G)] to get the f(t,x) the delay...

Look at your formula for horsepower.. It only depends on the instantaneous values of torque and RPM, not on any changes.

Mute, Did what you suggested and came up with U(s,x)=1/s*e^[-x*(s^2+Ds)/(Bs+C)] No way can I invert this monster. Tried Wolfram-alpha for some values of x,D,B,C to no avail. Any further thoughts? Thanks again for you interest.

No takers, So I simplified and here is the new version. Forget the physics. A(d^2T/dt^2)+B(d^2T/dtdx)+C(dT/dx)+D(dT/dt)=0 T(t,0)=T0 T(0,x)=0 Need T(t,x) 0<x<L I did a numerical solution using excel, but I would prefer a closed form one. It has been a long time since I have studied PDE's,so...

Thank you for responding In engineering it is common in these cases to assume no variation radially for the water inside the pipe since the flow is turbulent and no variation radially for the pipe owing to its thin wall and high conductivity.

What, no takers?? Let me add the ODE equations I formulated : A*(dT/dx) +B*(dT/dt)+D*T=D*Tm C*(dTm/dt)+D*Tm=D*T A,B,D,C constants the d/dt and d/dx operators are partial derivative operators T= temperature of water Tm=temperature of pipe I eliminated Tm from the set and got a hypergeometric...

The problem: Appreciate help on the following Hot water flows in an insulated copper pipe L long starting at temperature, T0 Need the temperature history, T(t,x). T(0.x)=0 T(t,0)=T0 Heat transfer coefficient(conductance) water to pipe is U. Pipe heat capacity per unit length is C I...