HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Blogs
Guest Blogs

Understanding the Fluid Dynamics of Boundary Layers

NO RATINGS
View Comments: Newest First|Oldest First|Threaded View
William K.
User Rank
Platinum
Re: BOUNDARY LAYER
William K.   3/10/2014 10:12:04 PM
NO RATINGS
Joe, actually I did the "books" part of the study quite a few years back. That is when I ran into that irritating "reynolds number" limitation on fluid velocity. But there was enough understanding to allow me to solve our problem. But then we discovered that oher things made the project impossible, and quite expensive as well. On top of that, and best of all, the particulat rule that was driving the development did not get passed. So when the mandate to do the impossible is removed, prudence and wisdom dictate stopping the project.

Of course a general understanding of fluid dynamics is indeed handy in everyday life, I find.

Joe Panfalone
User Rank
Blogger
Re: BOUNDARY LAYER
Joe Panfalone   3/10/2014 9:51:13 AM
NO RATINGS
You are spot on. I am glad that someone actually went back to the books on this one.

Joe Panfalone
User Rank
Blogger
Re: useful information
Joe Panfalone   3/10/2014 9:24:22 AM
NO RATINGS
I tried to keep it generic without promoting our products but since you asked, it was one of the EXAIR air knives. Also one of my Colleagues had a similar application trying to get under the boundary layer to remove static electricity. If you are interested he did a write up in it http://blog.exair.com/?s=boundary

 

bobjengr
User Rank
Platinum
BOUNDARY LAYER
bobjengr   3/8/2014 2:52:36 PM
NO RATINGS
Very good article Joe.  Excellent review.  I had to go back and pull out the book on this one. Pao describes boundary layer as follows: " Since the fluid adheres to the solid boundary, the frictional forces retard the motion of the fluid in a thin boundary layer.  Within the boundary layer the fluid velocity increases from zero at the solid surface to that of the main stream of fluid flow".   He also mentiones the velocity distributio within the boundary layer is influenced by the fluid velocity.  The smaller the viscosity the thinner the boundary layer. Again--great review. 

William K.
User Rank
Platinum
Re: useful information
William K.   3/8/2014 7:44:20 AM
NO RATINGS
Joe, this is an interesting tale. BUT what was the final solution? I can immagine a few baffles set close to alter the airflow as being the cheapest appraoch, although an air knife of some sort would possibly be the simplst.

And I know that fluid dynamics, for gasses, at least, is just a mix of inertia, friction, compression, and elasticity, with those last two being opposite sides of the same coin. And someplace in there comes the Reynolds number, which is sometimes a very limiting factor. That is probably why the CFD programs are so very useful. But thanks for an interesting post. I had not considered the possibility of a thermal priner having that type of problem. I wonder how an ink-jet printer would have worked in that instance.

Joe Panfalone
User Rank
Blogger
Re: useful information
Joe Panfalone   3/7/2014 8:20:45 AM
NO RATINGS
Thank you. Most applications concerning boundary layer deal with drag so I thought it would be of interest to highlight another less known application. I try to write in layman's terms so the less mathematical inclined can understand.

 

naperlou
User Rank
Blogger
useful information
naperlou   3/6/2014 1:59:35 PM
NO RATINGS
Joe, very good article.  This is useful information for people working with moving manufacturing processes.  I basically knew the concept, but it's appearance in these types of applications is new to me.

Partner Zone
More Blogs from Guest Blogs
With strong marketplace demand for qualified engineers across the board that currently outstrips the available supply, there may never be a better time for engineers and project managers to advance their careers and salaries. Whether those moves are successful in the short-term and long-term is likely to depend on how the transition from one job to the next is handled.
There are drivers everywhere who turn on their headlights or windshield wipers with no awareness of the development effort behind a switch. Yet from freezing winter to sweltering summer, on dull rainy days and in bright sunshine, switches are expected to function consistently for the lifetime of a car.
Jet engine maker Pratt & Whitney sees additive manufacturing as a production approach that's complementary to -- not a replacement for -- traditional manufacturing processes.
The standards electrical machines and components are required to meet in the food processing industry are far more stringent than those in traditional plant construction. For specialized production environments such as these, components must not only resist thermal and physical stresses, but they must also be resistant to the chemicals used to sterilize equipment.
The word “smart” is becoming the dumbest word around. It has been applied to almost every device and system in our homes. In addition to smartphones and smart meters, we now hear about smart clothing and smart shoes, smart lights, smart homes, smart buildings, and every trendy city today has its smart city project. Just because it has a computer inside and is connected to the Web, does not mean it is smart.
Design News Webinar Series
2/25/2015 11:00 a.m. California / 2:00 p.m. New York
12/11/2014 8:00 a.m. California / 11:00 a.m. New York
12/10/2014 8:00 a.m. California / 11:00 a.m. New York
11/19/2014 11:00 a.m. California / 2:00 p.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Mar 9 - 13, Implementing Motor Control Designs with MCUs and FPGAs: An Introduction and Update
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  67


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2015 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service