Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

frictional loss calculation of a fluid between a rotating disc and a wall

frictional loss calculation of a fluid between a rotating disc and a wall

frictional loss calculation of a fluid between a rotating disc and a wall

I'm looking into the frictional loss of fluid between a rotating disc and a wall. Many works have been done for rotating cylinder inside a stationary tube, so I was trying to use that to come up with an equation to estimate the frictional loss.

s - the uniform gap between the disc and the wall
r2, r1 - OD and ID of disc
w - constant disc rotation

Not sure if anyone has done this before, but would love to get feedbacks on my calculation. I'm not so sure about my double integral and also my last integral.

RE: frictional loss calculation of a fluid between a rotating disc and a wall

Your equations appear to assume laminar flow, which may or may not be correct.

There is a famous paper by Theodore Von Karman, written in 1921 (in Aachen, so it's in German), that covers the topic of drag on a rotating disc, both as a numerical solution (one of the few problems involving the full Navier Stokes equations that can be directly solved with classical methods), and with comparison to test data. An English translation of that paper should be available in NASA archives.

Or you can look at the wikipedia article here:


RE: frictional loss calculation of a fluid between a rotating disc and a wall

Thanks @btrueblood for the direction. This was helpful. I was reading Saari's Thermal Analysis of High-speed Induction Machines. He referenced Daily and Nece 1960, which addressed laminar and turbulent friction coefficient. I was wondering if you have come across this before. Regime I and laminar equation given in von Karman are pretty similar. Regime III and turbulent equation and von Karman are a little different.

For Saari's reference, I'm a little confused with s/r1 term in the equations. In the figure description and y-axis of the graph, it uses s/r2 as spacing ratio, but the equations all use s/r1. I wonder if that's a typo.

RE: frictional loss calculation of a fluid between a rotating disc and a wall

I think I agree that it's a typo, and would trust the equations until proved otherwise.

The turbulent b.l. equations will vary depending on the turbulence model used (and there are a plethora of them). For all of the research over the years since Von Karman, there is a lot of conflicting information in the literature, and things get weirder as you discuss shrouding the disk, and heat transfer. Confusing, at the least.

There are also a lot of papers written by a prof. Owens, J., at Bath University in England regarding shrouded disks, dating from the 80's up to the early 2000's at least. He's likely retired by now, but may have a replacement continuing his work (he collaborates (-ed?) quite a bit with Rolls Royce). Was helpful when I contacted him back in the early 2000's, though we didn't have sufficient funds at the time to hire him as a consultant.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close