Critical depth not calculated?

[RPL]

Apologies if this is too basic of a question for this forum.

I created a very simple (9 x-sections) model of a natural channel. The profile it creates (and the summary results table) only shows a critical depth for the downstream section.

There are errors, warnings, etc pertaining to split flow (valid), velocity head change, conveyance ratio, but do not seem to indicate a major flaw. Flow is confirmed to be subcritical at the downstream section, average velocities are 4 – 6 fps, bed slope is about 0.3%. I’m using known WSE’s for the downstream boundary condition. (It does the same thing when I use normal depth/downstream slope…)

Is there some simple explanation for this? I have not seen it before, though I have only created a half-dozen or so models.

[Hydrojock]

Hello RPL

It sounds like you have a simple issue. There is an option in steady flow analysis where you can specify if you want RAS to calculate critical depth at all cross sections. By default, it does not – only calculating it where it is necessary. The User’s Manual goes into this in detail.

Go to the Steady Flow Analysis and select Options. Then select Critical Depth Output Option and choose Critical Always Calculated. When you re-run your model, you should have critical depth solved at all locations.

Regards,
James Heyen, P.E., CFM
Senior Hydraulic Engineer
WEST Consultants, Inc.

[RPL]

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From: Rod Lundberg
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Subject: RE: Critical depth not calculated?
Date: Wed, 18 Sep 2013 07:15:52 -0700
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Thanks very much=2C hydrojock! I’m sure that is it. I forgot that all of =
my previous work in HEC-RAS had been with a model package that someone had =
already been working with and had all the basic settings established… duh=
!
=20
rpl
=20
Date: Fri=2C 13 Sep 2013 11:09:25 -0700
From: [email protected]
To: [email protected]
Subject: Re: Critical depth not calculated?

=0A=
=0A=
Hello RPL=0A=

It sounds like you have a simple issue. There is an option in steady flow =
analysis where you can specify if you want RAS to calculate critical depth =
at all cross sections. By default=2C it does not – only calculating it whe=
re it is necessary. The User’s Manual goes into this in detail.=0A=

Go to the Steady Flow Analysis and select Options. Then select Critical De=
pth Output Option and choose Critical Always Calculated. When you re-run y=
our model=2C you should have critical depth solved at all locations.=0A=

Regards=2C=0A=

James Heyen=2C P.E.=2C CFM=0A=

Senior Hydraulic Engineer=0A=

WEST Consultants=2C Inc.=0A=
=0A=
=0A=
=0A=
=0A=
=09
=0A=
=09
=0A=
=0A=
=0A=
If you reply to this email=2C your message will be added to the discussio=
n below:=0A=
http://hec-ras-bloggery-forum.1091112.n5.nabble.com/Critical-depth-not-ca=
lculated-tp326p329.html=0A=
=0A=
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To unsubscribe from Critical depth not calculated?=2C click here.
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Content-Transfer-Encoding: quoted-printable

Thanks very much=2C hydrojock!&n=
bsp=3B I’m sure that is it.&nbsp=3B I forgot that all of my previous work&n=
bsp=3Bin HEC-RAS had been with a model&nbsp=3Bpackage that someone had alre=
ady been working with and had all the basic settings established… duh!&nbsp=3B
rpl
&nbsp=3B

---

Date: Fri=2C 1=
3 Sep 2013 11:09:25 -0700
From: [email protected]
=
To: [email protected]
Subject: Re: Critical depth not calculated?
=0A=
=0A=
Hello RPL=0A=

It sounds like you have a simple issue. &nbsp=3BThere is an option =
in steady flow analysis where you can specify if you want RAS to calculate =
critical depth at all cross sections. &nbsp=3BBy default=2C it does not – o=
nly calculating it where it is necessary. &nbsp=3BThe User’s Manual goes in=
to this in detail.=0A=

Go to the Steady Flow Analysis and select Options. &nbsp=3BThen sel=
ect Critical Depth Output Option and choose Critical Always Calculated. &nb=
sp=3BWhen you re-run your model=2C you should have critical depth solved at=
all locations.=0A=

Regards=2C=0A=

James Heyen=2C P.E.=2C CFM=0A=

Senior Hydraulic Engineer=0A=

WEST Consultants=2C Inc.=0A=
=0A=
=0A=
=0A=
=0A=

=0A=

=0A=

---

=0A=

=0A=

If you reply to this email=2C your me=
ssage will be added to the discussion below:

=0A=
http://hec-ras-blogge=
ry-forum.1091112.n5.nabble.com/Critical-depth-not-calculated-tp326p329.html=
=0A=

=0A=

=0A=
=0A=
To unsubscribe from Critical depth not calculated?=2C click here.
=
=0A=
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=

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[Anonymous]

really THANK u so much,you solve one of my biggest problem

[Author]

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