Re: [Anuga-user] Simulation of bores

[Ananth W. <a.w...@uq...>]

Hi Stephen and Gareth,

Thanks for the suggestions.

I'm currently using file_boundary that specifies the stage and x-momentum, y-momentum with time for the inflow boundary condition. Attached is a sample inflow condition. In my case, i have both stage as well as momentum as input boundary condition but still the wave height dissipates.

If my understanding is correct, the above "Transmissive_n_momentum_zero_t_momentum_set_stage_boundary" would conserve momentum with a given stage boundary condition where inflow momentum is not known, is it correct? I tried using this as inflow boundary but the waves still dissipate as much as before with file_boundary.


Best regards,

Ananth.



Ananth Wuppukondur

B.Tech, M.S (by Research)

PhD Candidate

School of Civil Engineering

The University of Queensland

Brisbane Qld 4072 Australia

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________________________________
From: Gareth Davies <gar...@gm...>
Sent: Tuesday, May 14, 2019 13:07
To: anu...@li...; Ananth Wuppukondur
Subject: Re: [Anuga-user] Simulation of bores

Just adding to Steve's boundary-condition point here -- which I agree with -- I have seen problematic models where the incoming stage was specified along with zero momentum. This can cause severe reductions in wave-height near the boundary if the true momentum is not negligible (e.g. typical situation for an offshore tsunami boundary condition). The boundary condition Steve mentions should not do that.


On 14/5/19 1:01 pm, Stephen Roberts wrote:

Hi Ananth,


I would suggest looking at the boundary condition  for the Okushiri validation  test


validation_tests/experimental_data/okushiri, in particular the use of


Bts = anuga.Transmissive_n_momentum_zero_t_momentum_set_stage_boundary(domain, wave_function)



Also you might try the more accurate (though slower algorithm), DE1 instead of DE0, via a call to


domain.set_flow_algorithm('DE1')


How are you setting the BC at the moment?


Cheers

Steve


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________________________________
From: Ananth Wuppukondur <a.w...@uq...><mailto:a.w...@uq...>
Sent: Wednesday, 8 May 2019 7:17:46 PM
To: anu...@li...<mailto:anu...@li...>
Subject: [Anuga-user] Simulation of bores

Hi,

I'm simulating tsunami bores in ANUGA in a 9m long flume with stage and x momentum as input. The attached figure shows comparison of simulations with experimental measurements as well as another numerical model BASEMENT which is similar to ANUGA. Black lines are experimental measurements, red -ANUGA results and blue - BASEMENT results. If we see at the results, the simulations are underpredicted by upto 50% within a 8m reach in both the numerical models compared to experiments. The first curve is the input condition for the model and we can see that even the queried results at the input location are not simulated properly in the models to match with the given boundary conditions. The results are similar for different bore heights and velocities.

Also, if we look at the duration of the bore, it is around 3sec with a falling limb behind peak elevation. Instead of a falling limb behind the peak elevation, if I extend the duration of the peak elevation to 2 sec followed by a falling limb (making total duration of bore 5sec), the dissipation in the simulation results is not much compared to earlier case, which suggests this is something to do with duration of peak elevation in the bore.

Could you please suggest why there is huge dissipation of wave height in simulation of bores? The still water depth was 0.13m and bore height was around 7cm at the input.


Best regards,

Ananth.



Ananth Wuppukondur

B.Tech, M.S (by Research)

PhD Candidate

School of Civil Engineering

The University of Queensland

Brisbane Qld 4072 Australia

M +61 0431 453 828

E a.w...@uq...<mailto:a.w...@uq...>

w Personal webpage<https://ananthwsharma.wixsite.com/ananthwuppukondur> Google scholar<https://scholar.google.ca/citations?user=AROgxX4AAAAJ&hl=en> ResearchGate<https://www.researchgate.net/profile/Ananth_Wuppukondur> LinkedIn<https://in.linkedin.com/in/ananth-wuppukondur-a37a6048>

CRICOS code: 00025B
[cid:par...@gm...]


The University of Queensland is embracing the Green Office philosophy. Please consider the environment before printing this email.

This email (including any attached files) is intended solely for the addressee and may contain confidential information of The University of Queensland. If you are not the addressee, you are notified that any transmission, distribution, printing or photocopying of this email is prohibited. If you have received this email in error, please delete and notify me. Unless explicitly stated, the opinions expressed in this email do not represent the official position of The University of Queensland.







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