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TOPIC: Wind in Blue kenue

Wind in Blue kenue 5 years 8 months ago #33026

  • jonathan
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Hello all,

I would like to run a 2D telemac model using the mesh i created in blue Kenue wiht wind data in it (constant during all the simulation). I would like to incorporate the wind from North East and in an other model a wind from South West. I understood that to do it i will have to add avriables in my selafin file called wind along X and wind along Y, How ever i cant find any tutorial about it, so i have few questions:

For a North East wind (50 degrees), with a speed value of 10m/s, how do I enter that in Blue kenue?
Do i have to create a new closed line for both wind along X and Y and should i use the pythagor theroem to enter the value among X and Y?
Is there an easiest and fastest way to do it?
Would it be taking into account in Telemac? If not, How do i wirte it down in the cas file?


Thank you very much by advance
Regards


Jonathan
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Wind in Blue kenue 5 years 8 months ago #33030

  • c.coulet
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Hi Jonathan
If you just want a constant wind in space and time this will be much more easier to just use the dedicated keyword in the steering file...
Your solution is more for spatial varying wind...
Look at the wind example

Regards
Christophe
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Wind in Blue kenue 5 years 8 months ago #33034

  • jonathan
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Hi Christophe,

First thank you for your answer and sorry i was not clear, i want the wind to be constant in speed and time but not in space. Indeed, depending on the area the wind can be only north. So if its a north wind basically the X value will be = 0 but in a case of a North East, how do i do it with Blue Kenue?

regards

Jonathan
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Wind in Blue kenue 5 years 8 months ago #33036

  • c.coulet
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Hi
You should do as you think:
Create both wind variable in BK for values in X and Y
Compute the cosine and sine values of your wind direction to obtain the X and Y component of your wind.
Create one ore more closed line for the different area of wind field and give them the computed values
Finally map these values on your mesh

I don't see any other solution to do that

Regards
Christophe
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Wind in Blue kenue 5 years 8 months ago #33067

  • jonathan
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Thank you very much!!

Regards
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Wind in Blue kenue 5 years 8 months ago #33070

  • jonathan
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Sorry i dont understand what do you mean by compute? using pythagore theoreme?

The wind strength is 4 m/s (hypothenuse)
the wind direction is approximately NE (60 degrees)

that would mean: X= -3.81 and Y= -1.22.

Is that the right thing to do?

regards
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Wind in Blue kenue 5 years 8 months ago #33072

  • c.coulet
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Pythagore is not sufficient as it cannot give you the value on X and Y by only knowing the hypothenuse
If the wind blows from 60°/North
for me you should have
x = cos(210°)*4 = -3.4641
y = sin(210°)*4 = -2

Regards
Christophe
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Wind in Blue kenue 5 years 8 months ago #33086

  • jonathan
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Ok, I dont understand where the 210 comes from, could you explain it to me please?

Regards
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Wind in Blue kenue 5 years 8 months ago #33088

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60° from North is equal to 30° x-axis
As the wind blows from, we add 180° and obtain 210°
So the wind blows to 210° (trigonometric direction)
regards
Christophe
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Wind in Blue kenue 5 years 8 months ago #33103

  • jonathan
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Thank you very much for your answer. I ran the model with the wind into blue kenue and did it not change the velocity at all... So i will try to add the wind in the sterring file instead.

I added it in the section Physical parameters, Could you please tell me if this is correct?

OPTION FOR WIND = 1
WIND VELOCITY ALONG X = -3.151
WIND VELOCITY ALONG Y = -2.464

Regards

File Attachment:

File Name: menai.cas
File Size: 4 KB
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