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# check file to check variable manning by depth in 2d

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Hi ,

I like to know whether there is a check file available in 2d check file, so can check and verify the input of variable manning by depth in 2d domain.

In my case, I am using variable manning by depth to simulate the effect from building, see the text from tmf file.

9, 0.020, 0.00, 0.0, 0.1, 0.02, 0.12, 0.30, , 0     ! Buildings

However I only can see the manning of 0.3 has been assigned to cells where the building are from 2d_grd check file. Wondering there is a check file or 2d_po time series data file can tell the true story behind the scheme.

Thanks

Henry

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Hi Henry,

There is currently no way to visualise the time series of Manning's n applied to your cell according to depth.

What I can recommend instead is the uvpt_check file; the Manning_n attribute contains the Manning's n at the highest depth.

This way you could ensure that the correct value is being applied in cells where depths less than your Maning's threshold are achieved.

The csv line above describes to me that you will have a manning's n of 0.02 until a depth of 0.1m, then a manning's n of 0.3 until 0.12m, then manning's n or 0.02 for depths above that.

Is this correct?

Cheers,

Rachel.

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Hi Rachel,

#9 - Material 9:
Manning's n vs Depth Curve:
#     Depth         n
1    0.1000    0.0200
2    0.1200    0.3000
IL = 0.0mm,  CL = 0.0mm/h
Landuse Hazard ID not set.
SRF (Storage Reduction Factor) = 0.05
Fraction Impervious = 0.

Cheers

Henry

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Hi Henry,

You should also be able to specify n in the Map Output Data Types.  E.g:

Map Output Data Types == h v q d n !level, velocity, unit flow, depth and Manning's n values.

This will output the Manning's data to your specified map format (e.g. .asc, .flt, .dat, .xmdf).

Cheers

Phil

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Sorry I'm a bit slow coming back with this, but just to avoid confusion by anyone reading these posts at a later date I wanted to clear up the interpretation of the line in the .TMF.

The manual states:

The fifth to eighth numbers are also optional and are used to change the Manning’s n value with depth.
The four values, y1, n 1, y2, n2, are applied as follows: below y1 metres deep, a Manning’s n value of n1
is applied; above y2, n2 is applied, and between y1 and y2, the Manning’s n value is interpolated
between n1 and n2 according to Bed Resistance Depth Interpolation.

And therefore the .TMF/.CSV line above describes to me that you will have a Manning's n of 0.02 until a depth of 0.1m and a Manning's n of 0.3 at depths greater than 0.12m, with an interpolated roughness inbetween. Finally, the 0.02 in column 2 is never actually used if a depth varying roughness is applied.

At least, that's how I've always understood it! Please let me know if I'm wrong!

PHA.

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