Heat Wave Equations: Explaining Delta t & x Approach to Zero

  • Context: Undergrad 
  • Thread starter Thread starter Kajan thana
  • Start date Start date
  • Tags Tags
    Heat Wave
Click For Summary

Discussion Overview

The discussion revolves around the mathematical interpretation of limits as delta t and x approach zero in the context of heat wave equations, specifically addressing the definition and implications of the variable ##\kappa##.

Discussion Character

  • Technical explanation, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant suggests that as delta t and x approach zero, it results in the whole fraction being zero, while the slide indicates it results in ##k^2##.
  • Another participant questions whether this is simply the definition of ##\kappa##, noting that the limit is not negative and can be defined as the square root of it.
  • A participant expresses confusion about whether the definition of ##\kappa## is indeed mathematical, seeking clarification on this point.
  • Another participant agrees that the limit is some value and proposes that ##\kappa## can be defined as the square root of that limit, indicating that the limit equals ##\kappa^2##.

Areas of Agreement / Disagreement

Participants express differing views on the interpretation of the limit and the definition of ##\kappa##, indicating that the discussion remains unresolved.

Contextual Notes

There are limitations regarding the assumptions made about the behavior of the limit as delta t and x approach zero, and the definitions of the variables involved are not fully clarified.

Kajan thana
Messages
149
Reaction score
18
TL;DR
Hi Guys, I am trying to understand the derivation of the diffusion/heatwave equation, but I am stuck on how the person managed to get ##k^2##. I have attached the slide to this thread.
When the delta t and x approached zero, assumably it results in the whole fraction to be zero. The slide shows it will be ##k^2##. Can someone explain this to me, please?
1607905475409.png


P.S. I have tried to search this up, I could not find anything related to the confusion.
 
Physics news on Phys.org
Are you sure this isn't simply the definition of ##\kappa##? The limit is not negative, so you can define ##\kappa## to be the square root of it. It's a kappa, not k.
 
  • Like
Likes   Reactions: Kajan thana
mfb said:
Are you sure this isn't simply the definition of ##\kappa##? The limit is not negative, so you can define ##\kappa## to be the square root of it. It's a kappa, not k.
First of all , thank you for the instant reply! But I am still confused.. is that the mathematical definition for the ##\kappa##?
 
I think so. The limit is some value, you define ##\kappa## to be the square root of that limit, i.e. the limit is ##\kappa^2##.
 
  • Informative
Likes   Reactions: Kajan thana

Similar threads

  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 1 ·
Replies
1
Views
3K
  • · Replies 6 ·
Replies
6
Views
858
  • · Replies 65 ·
3
Replies
65
Views
8K
  • · Replies 8 ·
Replies
8
Views
4K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 19 ·
Replies
19
Views
3K
  • · Replies 21 ·
Replies
21
Views
2K