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 » sci.math.* » sci.math.num-analysis

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

Topic: ? influence of temporal discretization
Replies: 1   Last Post: May 30, 2012 10:12 AM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View  
Dieter Britz

Posts: 20
Registered: 6/17/10
Re: ? influence of temporal discretization
Posted: May 30, 2012 10:12 AM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

On Fri, 25 May 2012 09:41:02 +0000, AMX wrote:

> On Sat, 19 May 2012 05:02:55 -0700 (PDT), Cosine <>
> wrote:

>> Hi:
>> Suppose we have a diffusion eqn: dT/dt = a*div(grad(T))+Q in non-
>> dimensional form.

> [..]

>> Can we discretize the time using dt as 0.1 sec or should we use a dt
>> even smaller? How do we estimate the appropriate value of dt?

> It mostly depends on method of integrating over time.

For any method of time integration, you can measure the order wrt dt
and get an estimate of the error by setting the spatial intervals
very small, and trying with dt, dt/2 and dt/4, choosing some resulting
quantity as the test, say q1, q2, q4, resp. Then q1 - q4 is close to
the error, and log_2 of the ratio (q1 - q2) / (q2 - q4) gives you the
order wrt dT.
Dieter Britz

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.