×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Mathcad help finding variable value

Mathcad help finding variable value

Mathcad help finding variable value

(OP)
I have a set of results from a simulation, in the form of a velocity along with the corresponding distance from the pipe centre. There are about 20 points.

I also have an equation that tries to model this, so i can enter in the same distances from the pipe centre and i want the output to be as close as possible to the simulation velocities.

To do this i have added some variables (at the moment 1 ("b") but i may progress to have 2 variables) to my formula which i wish mathcad to define for me...

How do i go about this, i have tried but, very, unsuccessful

Thanks in advance,

RE: Mathcad help finding variable value

MathCad does units REALLY well.  Not using them is totally irresponsible.  In your sheet you define R:0.1524.  Well if you'll let it, MathCad will call "R" "temperature in degrees Rankine".

If I can puzzle out where you started, it looks like
"d" is density and if I assume water, then it is in kg/m^3
"v" is viscosity (I'll assume 20C) in N*s/m^2
"R" is radius and I'll guess it is in m
"Vm" by process of eliminiation it must be mean velocity in m/s

Those assumptions get to the Reynolds Number you calculated.

Given that, I couldn't get the solve block to converge.  Why are you trying to use "find" instead of "genfit"?  I don't think that MathCad will do a "find" with an imbeded array.

David

RE: Mathcad help finding variable value

IRstuff,
That answer gives you a different "b" for every "r".  He's looking for a single "b" that generates a data set that matches "v".

David

RE: Mathcad help finding variable value

Dang, that is what I told him 2 days ago.

David

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


Resources

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