How Do You Rescale the Dimensionless Riccati Equation?

  • Thread starter Thread starter fresh
  • Start date Start date
  • Tags Tags
    Ode
Click For Summary

Discussion Overview

The discussion revolves around the rescaling of the dimensionless Riccati equation, specifically transforming the equation (dh/dt) = s - a*p*g*(h + (h^2)/R) into the dimensionless form y' = a - y - y^2. Participants are exploring methods to achieve this transformation and addressing challenges related to both the rescaling process and finding solutions.

Discussion Character

  • Exploratory, Technical explanation, Homework-related

Main Points Raised

  • One participant expresses difficulty in obtaining the dimensionless form of the Riccati equation and seeks assistance.
  • Another participant questions whether the difficulty lies in obtaining the dimensionless equation or in solving it, prompting further clarification on the participant's progress.
  • A participant indicates uncertainty about the necessary substitution for rescaling and requests guidance to proceed independently.
  • A suggestion is made to use substitutions h = Ay and t = Bx with constants A and B, and to choose these constants to transform the original differential equation into the desired form.

Areas of Agreement / Disagreement

Participants do not appear to have reached a consensus, as there are multiple approaches suggested and ongoing uncertainty regarding the rescaling process.

Contextual Notes

Participants have not specified the values or relationships for the constants A and B, nor have they detailed the assumptions underlying their proposed substitutions.

fresh
Messages
17
Reaction score
0
Been working on this problem for an hour now.

Rescale

(dh/dt) = s - a*p*g*(h + (h^2)/R)

to obtain the dimensionless ODE

y' = a - y - y^2

It seems that the differential equation involving dh/dt is a ricatti equation and I tried finding a particular solution but have had no luck. Any help is welcomed.

Thanks.
 
Physics news on Phys.org
Are you having difficulty obtaining the dimensionless equation or in solving it? In either case, what have you done so far?
 
I am having difficulty with the dimensionless part. I am really not sure what to do. I would think that you would need to make a substitution but i am not sure what. I just need a push in the right direction since I want to solve it myself.
 
There are several ways to approach it. Here's one: Let h = Ay and t = Bx with constants A and B. y and x will be your new variables. Substitute into the DE then choose A and B to put the new DE into the required form.
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
3K
Replies
3
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
Replies
8
Views
2K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 28 ·
Replies
28
Views
3K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K