model of small laboratory flume

[Anonymous]

I teach a basic hydraulics course and would like to use RAS to model different flow scenarios in the small flume (width =100 mm, length = 4 meter, height = 300 mm). I have had some success with steep slope models (4% or greater, even including hydraulic jumps). The students collect flume data and add to the model for calibration. I would like to model mild slope scenarios with bridge piers inserted into the flume. I created a cross section at station 0 and copied it to station 4 with a downstream reach length of 4 m and adjusted the elevations for a slope of 0.5%. When using the interpolation feature to add additional cross sections, oscillations in the bed are shown due to the very small elevation changes and presumably storage limitations. Anyone have suggestions to get around this? Thanks!

[Chris G.]

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Subject: Re: model of small laboratory flume
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Hi Jason-

Try this: http://hecrasmodel.blogspot.com/2008/12/extra-precision-in-interp=
olated-cross.html

Let me know if it works.=20
Chris

Sent from my iPhone

> On Sep 4, 2014, at 9:24 AM, “Jason Hill [via HEC-RAS Help]” wrote:
>=20
> I teach a basic hydraulics course and would like to use RAS to model diffe=
rent flow scenarios in the small flume (width =3D100 mm, length =3D 4 meter,=
height =3D 300 mm). I have had some success with steep slope models (4% or=
greater, even including hydraulic jumps). The students collect flume data a=
nd add to the model for calibration. I would like to model mild slope scena=
rios with bridge piers inserted into the flume. I created a cross section a=
t station 0 and copied it to station 4 with a downstream reach length of 4 m=
and adjusted the elevations for a slope of 0.5%. When using the interpolat=
ion feature to add additional cross sections, oscillations in the bed are sh=
own due to the very small elevation changes and presumably storage limitatio=
ns. Anyone have suggestions to get around this? Thanks!=20
>=20
> If you reply to this email, your message will be added to the discussion b=
elow:
> http://hec-ras-help.1091112.n5.nabble.com/model-of-small-laboratory-flume-=
tp927.html
> To unsubscribe from HEC-RAS Help, click here.
> NAML

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Hi Jason-

Try this:  http://hecrasmodel.blogspot.com/2008/12/extra-precision-in-interpolated-cross.html

Let me know if it works. 

Chris

Sent from my iPhone

On Sep 4, 2014, at 9:24 AM, “Jason Hill [via HEC-RAS Help]” <[email protected]> wrote:

I teach a basic hydraulics course and would like to use RAS to model different flow scenarios in the small flume (width =100 mm, length = 4 meter, height = 300 mm).  I have had some success with steep slope models (4% or greater, even including hydraulic jumps).  The students collect flume data and add to the model for calibration.  I would like to model mild slope scenarios with bridge piers inserted into the flume.  I created a cross section at station 0 and copied it to station 4 with a downstream reach length of 4 m and adjusted the elevations for a slope of 0.5%.  When using the interpolation feature to add additional cross sections, oscillations in the bed are shown due to the very small elevation changes and presumably storage limitations.  Anyone have suggestions to get around this?  Thanks!

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NAML

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[Anonymous]

Hello,
Sir, I have a query.
I am working with HEC-RAS for simulating my flume studies with a sand bed at the bottom.
Is it possible to get the bed elevation contour plots in Hec-Ras at the end of some flow happening for a particular period of time say 30 minutes or bed elevation changes?
If yes, please can u attach the procedure.
How were you able to get the bed oscillations you were mentioning?
and also how to set the bed to have the ripples pattern? I mean how to simulate it. it wold be nice if there is an example for flume studies.
A response and a set of instructions to follow would be largely helpful.

P.S I assume that you have figured out about all you asked.

[Anonymous]

I have used HEC-RAS to replicate a simulated dam break in a laboratory flume. The flume was a bit larger than the one that you are working with (4 ft. wide by 400 ft. long). My main interest was in comparing the HEC-RAS unsteady flow solution to a situation where the convective and local acceleration terms in the St. Venant equation were significant. A brief report is available at: https://www.dropbox.com/s/uuweuy72q18zmin/RAS%20replication.pdf?dl=0
Michael

[Anonymous]

Sir could you please share details of how you have modelled the flume used to simulate the dam break flow in a laboratory setup

Thank you.

[Author]

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