Search found 9 matches

by Manuela.Boehm
Wed Jul 17, 2019 1:31 am
Forum: Computer-Aided Engineering Software Tools
Topic: Phases of the diffraction forces
Replies: 2
Views: 309

Re: Phases of the diffraction forces

Hi Jason, Thanks for the comment on the phasing! I just realized that the phasing in my two different WAMIT files is very different, which leads to different amplitudes and phases of the total hydrodynamic forces. What I meant is that I thought that the drag force part remains equal when I use the s...
by Manuela.Boehm
Tue Jul 16, 2019 4:59 am
Forum: Computer-Aided Engineering Software Tools
Topic: Phases of the diffraction forces
Replies: 2
Views: 309

Phases of the diffraction forces

Hi all, I'm running simulation with a semi-submersible, using a hybrid solution of potential flow diffraction forces and morison drag terms. The model is fixed. I'm looking at total hydrodynamic forces and total wave-excitation loads from the diffraction in the frequency domain (singel sided amplitu...
by Manuela.Boehm
Tue Jul 09, 2019 2:17 am
Forum: General
Topic: Transient 'shut down' effect of the semi submersible
Replies: 4
Views: 960

Re: Transient 'shut down' effect of the semi submersible

Hi Jason,

I'm sorry, I was confused. I checked it again this morning, and it is only related to the signal length (the signal needs to be fully periodic). I was looking at the wrong data last night.

Best regards,

Manuela
by Manuela.Boehm
Mon Jul 08, 2019 11:34 am
Forum: General
Topic: Transient 'shut down' effect of the semi submersible
Replies: 4
Views: 960

Re: Transient 'shut down' effect of the semi submersible

Hi Jason, my first guess was that this is somehow related to the FFT, too. But it only occurs when the platform is floating. When I use the same model and the same wave elevation input in a constrained configuration, the second order wave signal look clean. Maybe it's somehow related to the motion c...
by Manuela.Boehm
Wed Jul 03, 2019 4:14 am
Forum: General
Topic: Transient 'shut down' effect of the semi submersible
Replies: 4
Views: 960

Transient 'shut down' effect of the semi submersible

Hi everybody, I'm running simulations with hydrodynamics only. My model is the OC5 semi submersible and I'm using a hybrid (potential flow + drag terms of morison equation approach. My wave input is a file in the GHbladed format, containing the wave elevations of a bichromatic wave load case. Wave E...
by Manuela.Boehm
Tue Nov 13, 2018 8:23 am
Forum: General
Topic: Simulating IEC DLC 1.6
Replies: 1
Views: 1598

Simulating IEC DLC 1.6

Dear all, I'm running extreme load analysis with FAST for jacket substructures. While looking further into the selection of simulation parameters I came across this clause in IEC 61400-3: “Calculation of DLC 1.6b may be omitted if in the treatment of DLC 1.6a, the non-linear wave kinematics are prop...
by Manuela.Boehm
Tue May 15, 2018 3:14 am
Forum: Computer-Aided Engineering Software Tools
Topic: The wave direction spreading coefficient
Replies: 2
Views: 638

Re: The wave direction spreading coefficient

Thank you for the link to the paper! That is exactly the background information I was looking for.

Best regards,

Manuela
by Manuela.Boehm
Mon May 14, 2018 8:37 am
Forum: Computer-Aided Engineering Software Tools
Topic: The wave direction spreading coefficient
Replies: 2
Views: 638

The wave direction spreading coefficient

Hi, I have a question concerning the wave spreading implemented in HydroDyn: As far as I understand the theory behind the cos-2s-spreading function, the wave direction spreading coefficient (s) controls the "concentration" of the directional distribution of the wave energy. A small "s...
by Manuela.Boehm
Wed Apr 18, 2018 7:47 am
Forum: Computer-Aided Engineering Software Tools
Topic: 2nd Order Waves- proper upper cut-off frequency for sum-frequency terms (WvHiCOffS)
Replies: 1
Views: 602

2nd Order Waves- proper upper cut-off frequency for sum-frequency terms (WvHiCOffS)

Hello, I would like to include 2nd- order wave kinematics into my simulation. I would choose the lower and upper cut-off frequencies for the difference- frequency terms as recommended in the hydrodyn manual (WvLowCOffD=0, WvHiCOffD=2 π/Tp). Is that correct? For the second-order sum- frequency terms ...

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