How Do Viscous Interactions Differ in Vertical and Horizontal Geometries?

  • Thread starter Thread starter HighPhy
  • Start date Start date
  • Tags Tags
    Viscous flow
Click For Summary

Discussion Overview

The discussion revolves around the differences in viscous interactions in vertical and horizontal geometries, particularly through experiments involving a sphere moving in a fluid. The focus is on understanding the implications of these interactions in the context of "Falling ball viscometry" and horizontal viscous flow, exploring both theoretical and experimental aspects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant describes an experiment involving a sphere in a vertical tube, measuring ascent times to calculate the viscosity coefficient, while noting the influence of buoyancy and viscous resistance.
  • Another participant suggests that the equations used for calculating terminal velocity may only be valid for horizontal pipes without buoyancy, indicating that vertical configurations complicate the analysis.
  • There is mention of the need to consider different flow regimes, such as creeping flow and turbulent flow, and the applicability of Bernoulli's equation in the presence of viscous forces.
  • One participant provides a link to a resource that discusses correction factors for scenarios where the sphere radius is not negligible compared to the pipe radius and where the Reynolds number is not very low.
  • Participants express the desire to explore the differences in velocity when the sphere is stationary versus when it is allowed to move within the tube.

Areas of Agreement / Disagreement

Participants have not reached a consensus on the implications of vertical versus horizontal geometries for viscous interactions. Multiple competing views remain regarding the applicability of certain equations and the effects of buoyancy and flow conditions.

Contextual Notes

The discussion highlights limitations related to the assumptions made in the experiments, such as the dependence on the size of the sphere relative to the tube and the Reynolds number conditions. The applicability of Bernoulli's equation is also questioned in the context of viscous flows.

  • #31
Chestermiller said:
Do you know what to do next?
I have to show the following, right?

Chestermiller said:
Let ##h_0## represent the small minimum clearance between the sphere (in our problem) and the cylinder. Let z = 0 represent the axial coordinate of the center of the sphere. Show that, for axial locations on either side of the sphere close to this center location, the clearance can be approximated by the parabolic shape $$h(z)=h_0+\frac{z^2}{2R}$$
 
Physics news on Phys.org
  • #32
HighPhy said:
I have to show the following, right?
yes.
 

Similar threads

Undergrad Force applied on sphere by turbulent flow
  • · Replies 28 ·
Replies
28
Views
2K
What does this mean? (equation for viscous flows)
  • · Replies 4 ·
Replies
4
Views
2K
Calculating Velocity of Water Flow in Open Channel
  • · Replies 11 ·
Replies
11
Views
2K
Fluid Flow Problem-Viscous Flow
  • · Replies 5 ·
Replies
5
Views
3K
High School How does liquid starts moving when there is Pascal's law
  • · Replies 15 ·
Replies
15
Views
2K
How Do You Calculate Reynolds Number for Flow Exiting a Rectangular Duct?
  • · Replies 1 ·
Replies
1
Views
4K
Graduate Definition of Pressure: Force, Work Done, & Mechanical Energy
  • · Replies 1 ·
Replies
1
Views
3K
Graduate How Does Bernoulli's Equation Explain Fluid Dynamics?
  • · Replies 1 ·
Replies
1
Views
8K
Motion of a Cylinder: Angular Velocity & Horizontal Distance
  • · Replies 18 ·
Replies
18
Views
2K
Problem about Hagen-Poiseuille law and pump
  • · Replies 15 ·
Replies
15
Views
5K