Sunday, February 28, 2010

Earthquake in Chile!

Wow. That was scary! I was on my way to Concepcion to teach an HEC-RAS class for some students at the Universidad de Concepcion. Fortunately I decided to spend a few days in Santiago, before going to Conocepcion. I was on the 14th floor of the hotel, and had the fright of my life. The news has said the earthquake was an 8.0 Richter in Santiago. Wow! But everything is okay and I finally got internet back in my hotel room. Now I just have to wait for the airport to open so that I can get out of here. Needless to say, the class in Concepcion is cancelled. I'm very sad to see what has happened in Conce, and really hope that my friends and colleagues there are all okay.

Wednesday, February 24, 2010

Wind-induced waves in reservoirs.

Written by Chris Goodell, P.E., D. WRE | WEST Consultants
Copyright © RASModel.com. 2010. All rights reserved.

Though HEC-RAS has no function for computing wave heights, its a fairly simply procedure that can be done external to RAS and incorporated into your design, or breach assumptions.

There are equations for wave heights and run up as a function of wind speed, reservoir depth, and fetch length. You simply gather some historical wind data that you can assign probabilities to. Assign a wind direction (to be conservative, you can assume the longest fetch length, unless the wind never blows that way), then compute wave heights and run up for different frequencies of wind magnitudes. Which frequency you design to (100-year, 50-year, etc) is up to you and your client.

Here’s a good place to start:

http://140.194.76.129/publications/eng-manuals/em1110-2-1420/c-15.pdf

Here are some other interesting links that might lead to additional information:

http://wave.oregonstate.edu/

http://www.wldelft.nl/cons/area/wds/im/wave-dynamic-structure.pdf

Monday, February 8, 2010

Hydraulics Toolbox

Written by Chris Goodell, P.E., D. WRE | WEST Consultants
Copyright © RASModel.com. 2010. All rights reserved.

I don't want to use this blog as a platform to sell stuff, but I find this software very useful when doing RAS models. So much so, that I thought I'd post it just for anyone's information. The software is called "Hbox" which is short for Hydraulics Toolbox.






If you have any questions about Hbox, or want to try a demo version, send me an email...