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!
  • Students Click Here

*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

hydraulic head in control structure

hydraulic head in control structure

hydraulic head in control structure

On a typical flow splitter manhole with a weir on a drainage system, the water quality flowrate is sent to a pipe connected to a treatment train, and flows in excess of the water quality flowrate are sent through another pipe that acts as a high flow bypass. The low flow pipe for water quality flowrate is on the same side of the weir as the inlet pipe. The high flow bypass pipe outlet is on the other side of the weir. The weir is a simple concrete baffle wall.

If a turned down elbow is used on the low flow outlet pipe with an orifice on end of the turned down elbow, is the hydraulic head from the water surface elevation (or top of weir) to the center of the horizontal outlet pipe or to the bottom of the turned down elbow where the orifice is located? Text in design documents say the hydraulic head is to the "center of the orifice" but I believe that statement is meant for when there is an outlet pipe without a turned down elbow with orifice. Can someone please help jog my memory and clarify this for me? Thank you.

RE: hydraulic head in control structure

top of weir

RE: hydraulic head in control structure

Yes, top of weir, but measured to what when the low flow outlet is a turned down elbow with an orifice plate on the bottom of the elbow? Is it measured from the top of weir to the bottom of the turned down elbow where the horizontal orifice plate is located, or to the invert of the pipe outlet, center of pipe outlet or top of pipe outlet? Since the pipe outlet is going to an oil water separator where where when flowing the water level will be at or near the top of pipe inlet and outlet of the oil water separator, I'm thinking maybe the hydraulic head is the distance from the top of weir to the top of outlet pipe.

RE: hydraulic head in control structure

I assume the orifice is controlling the flow, so head is measured to the center of the orifice. If some other piping or fitting is controlling the amount of flow, than your orifice would be ineffective.

RE: hydraulic head in control structure

Thanks for you responses cvg. Follow-up question...if the orifice is controlling flow to the outlet, but the orifice is submerged, would the hydraulic head be the difference between the top of weir and the water level in the outlet pipe (water level in outlet pipe is a result of the flow allowed by the orifice), i.e. the water level in the outlet pipe essentially being a tail water elevation?

RE: hydraulic head in control structure

well again, same question - is the orifice controlling the flow? or is the inlet pipe or is the outlet pipe? If this is simply a submerged orifice, than use delta h.

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


White Paper - How ESI is Helping Move New Medical Device Product to Market Quicker & More Cost Effic
Early Supplier Involvement has long been a strategy employed by manufacturers to produce innovative products. Now, it almost seems like a necessity. Because decisions made in the design phase can positively affect product quality and costs, this can help add value to OEM bottom lines. This white paper will discuss many facets of ESI, including why it’s so valuable today, what challenges limit the benefits of ESI, how cost is impacted, and more. Download Now
White Paper - Moving to a Driverless Future
This white paper describes what we see as the best practices to support a sustainable engineering process for autonomous vehicle design. It exposes how to use simulation and testing in common frameworks to enable design exploration, verification and validation for the development of autonomous cars at a system, software and full-vehicle level to drive a mature product development process for automated driving. Download Now
Research Report - How Engineers are Using Remote Access
Remote access enables engineers to work from anywhere provided they have an internet connection. We surveyed our audience of engineers, designers and product managers to learn how they use remote access within their organizations. We wanted to know which industries have adopted remote access, which software they are using, and what features matter most. 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