Understanding the Divergence Operator for Time-Varying Vectors

Click For Summary

Homework Help Overview

The discussion revolves around the divergence operator applied to a time-varying vector field, specifically a fluid flow vector represented as u = u(x,y,z,t). The original poster seeks clarification on whether the divergence is defined for such vectors and how to approach the calculation.

Discussion Character

  • Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to understand the application of the divergence operator to a vector field that varies with time, questioning whether it is appropriate to treat time as a constant during differentiation. Some participants affirm that the divergence operator operates on spatial dimensions only, suggesting that time can be held constant during the calculation.

Discussion Status

The discussion is active, with participants providing insights into the nature of the divergence operator and its application to time-varying vectors. There is a consensus among some participants that the divergence involves partial derivatives with respect to spatial variables while treating time as constant.

Contextual Notes

The original poster expresses uncertainty about the definition of the divergence operator in the context of time-varying vectors, indicating a potential gap in understanding the operator's application in fluid dynamics.

tomwilliam2
Messages
117
Reaction score
2

Homework Statement



I'm trying to find the divergence of a vector field (a fluid flow vector), but the vector takes the form u = u(x,y,z,t)

The Attempt at a Solution



I only really know how to take the divergence of a time-independent vector, so I'm guessing I just take the partial derivatives with respect to x,y,z and hold t= constant...is that right?
I am interested in knowing whether the divergence operator is even defined for time-varying vectors, or whether divergence is only defined for a given point in time.

Thanks
 
Physics news on Phys.org
Del operates on spatial dimensions*. So yes, you just take the partial derivatives with respect to x, y and z.

*Unless otherwise specified.
 
Thanks very much.
 
I agree with DeIdeal. The divergence operator involves partial derivatives with respect to x, y, z and so t is treated as a constant.
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
2K
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
8
Views
3K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 43 ·
2
Replies
43
Views
5K