Recent content by robby991

Thank you for your response. I actually have been trying your second method, where j = time steps: \frac{Vmax*F(j+1)}{KM+F(j)} However, I guess my question is how to actually solve the matrix. If I set up my matrix of the form A*F(j+1) = B*F(j) then...

Does anyone have any idea how this V*F/K+F would be "linearized" and fit into the matrix?

Thank you both for your response. Based on your feedback, I am doing the crank nicholson implicit technique. I can code the diffusion equation in Matlab with the Crank Nicholson scheme using backslash divide on a martix, but there is an added term to the end of my equation that I do not know...

Hi, I am using the central difference method to solve a diffusion-based partial differential equation. However, my code now will not run because the time step has to be so large that Matlab cannot handle it. The large time step is due to the stability of stability: Diffusion...

Thank you, I understand now. I am evaluating this problem which I cannot duplicate the solution. It is as follows: ##i(t) =nDF\frac{\partial P}{\partial x} @ x = 0## Evaluating the following limit I = Lim i(t) as t→∞ by solving the following equations and boundary conditions...

Hi, I am trying to understand solving boundary valued partial differential equations and it's relation to hyperbolic functions. In one of my problems, there is a PDE and the solution contains the hyperbolic function "cosh". I was just curious if anyone has any information for me to read up on...

There is no flux at the end, it is a dirchelet boundary condition. S(:,numx) = S0; %S(x=d,t)=S0 P(:,numx) = 0; %P(x=d,t)=0 Yes, the interface node is: Ds1*dS1/dx = Ds2*dS2/dx Dp1*dP1/dx = Dp2*dP2/dx which I have evaluated in MATLAB as the following...

I ran into a little difficulty and was wondering if my scaling of parameters was correct in my code. Say I have a grid of length "Length", and instead of going from 0 to Length I want to scale from 0 to 1. In addition I have the following constants in my calculations: Length = 1E-4...

Here is my code: %{ Solution to the substrate and product diffusion equations using the central difference scheme with Neumann boundary conditions for S at x = 0, and dirchelet boundary conditions: S(:,numx) = S0; %S(x=d,t)=S0 P(:,1) = 0; %P(x=0,t)=0...

The system is as follows. Diffusion of 2 species, S and P, through 2 layers. First layer is 1E-6 second is 10E-9. The diffusion through layer 1 for S and P is: dS/dt = Ds1*d^2S/dx^2 - (vmaxS/km +S) dP/dt = Dp1*d^2P/dx^2 + (vmaxS/km +S) Diffusion through the second layer is...

Unfortunately there is no other option other than vectorizing. To keep the stability in my code, the dt has to be extremely small (total time is fixed), which makes the number of time steps in my matrix extremely large (on the order of 500000). Matlab either gives me a memory error or crashes...

Yus: Thanks this is great. I was going through the code and there are some things that are a little confusing to me. I understand the general heat equations and how you are calling the boundary conditions, however could you clearly state the problem at hand (purpose of pulse?) and boundary...

Thank you for the reply, I went through your code and it gave me different ideas on how to call initial and boundary conditions. This was only considered as a 1 layer system correct? One problem I cannot figure out, maybe you can help me, is how to vectorize this code (mine and yours) Right...

I have one last question regarding this. Do I have to scale the matrix vectors in the time domain also? I scaled all the parameters related to the space domain (x), but I also have the time vectors (y). If so, do I divide by the same constant I used to scale the space domain?

Hi everyone. I am still having issues implementing diffusion through 2 layers in Matlab. I attached my Matlab code using the information in my previous post. If anyone has any suggestions I'd appreciate the feedback. Somehow, I do not think I am implementing the equations right in my code...