The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » Software » comp.soft-sys.matlab

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: using solution of previous time step for DAE dde23 applicable
Replies: 0  

Advanced Search

Back to Topic List Back to Topic List  

Posts: 8
Registered: 5/24/13
using solution of previous time step for DAE dde23 applicable
Posted: Sep 24, 2013 10:59 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

Dear all,

i do have a PDE which describes sedimentation. I do discretize it in space and end up with a system of ode´s. Fairly simple.

Now i use the same PDE (settling of particles) inside a syringe (no particles leave the syringe) and move the piston (pressure filtration). Therefore i do have a moving boundary at the piston. So i have to solve for the piston height too. One boundary is in fact an algebraic equation.

The system looks like
solving for the piston height:

dh/dt=(height(n+1)-height(n))/dt = someODE

i=1 (Algebraic equation for boundary)
y(i) =h(n)/h(n+1)*(something)
dy/dt= dh/dt*(something discretized) + h(n)/h(n+1)*(something discretized)

My question is if i can use dde23 here or not ? I do have a published method with euler timestepping and i would like to use the comfort of a variable time stepping routine. ode23 works well for the simple cases with MOL.



Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.