Dimensional Analysis:Relating Particle Diam, Viscosity, & Weight

AI Thread Summary
The discussion focuses on determining the relationship between the terminal velocity of a spherical particle in a fluid and its diameter, dynamic viscosity, and buoyancy weight. The participant expresses uncertainty about their approach and seeks guidance on how to proceed. A suggestion is made to treat the buoyancy weight as a single term, simplifying the analysis. This clarification helps the participant realize they overlooked the relationship between the variables, leading them to derive an equation consistent with Stokes' law. The conversation emphasizes the importance of correctly defining terms in dimensional analysis.
evoke1l1
Messages
10
Reaction score
0

Homework Statement


It is found the terminal velocity ut of a spherical particle in a fluid depends upon the diameter d of particle, the dynamic viscosity μ of fluid and the buoyancy weight W of the particle [given by the difference in density between the particle and the fluid (∆ρ) × gravitational acceleration (g)]. Determine the nature of the relationship between these variables.

Homework Equations



The Attempt at a Solution

[/B]
image.png

image.png


I'm not quite sure if I'm on the right track and where to go next from here? Any guidance or a nudge in the right direction would be appreciated. I can't help but think I have gone slightly wrong due to the number of indices to solve for.
 
Physics news on Phys.org
Perhaps you should make the weight a single term? That is, treat ∆ρ⋅g as one term. That, after all, is how it is described in the problem statement.
 
  • Like
Likes evoke1l1
Thank you. That was a big help. I obviously missed taking ∆ρ⋅g as W and got stuck in a rut. The end equation I've now determined to be as per Stokes law.

Many thanks.
 
Back
Top