Optimization Of Bulbous Bows For Offshore Support Vessel

[Guest Mr. TAU SENG ANG]

Hi everyone, 

                      I am a beginner in using this software. I would like to know why i do not have the function to alter the Bulbous bows in Y direction. Is it because i am using the CAESES free version ? Because i am able to alter the bulbous bow in X and Z directions.

[Karsten Wenzke 12]

Dear Tau Seng Ang,

 

Thank you for posting this question.

 

Are you refering to a CAESES sample model?

It is possible to alter a bulbous in y directions.

 

Take a look at these samples.

You can find them in the documentation browser > samples > hull design > partial parametric modeling

 

The other hull design models might be of  interest for you.

 

If you have any other question do not hesitate to ask.

 

Cheers,

 

 

Karsten

[Guest Mr. TAU SENG ANG__0003]

Hi,

    nope,i am referring to the bulbous bow of the offshore support vessel sample's. It seems like I can't modify the bulbous bow in the y direction. I would like to enquire whether is there a way to modify the bulbous bow in y direction for this particular bulbous bow? 

[Matthias Maasch 21]

Dear Tau Seng Ang,

 

it is possible, but not to an exact value. Please see the attached modified sample project. The bulb is defined by a BSplineCurve running between the surface 8_fos2fwdBase and the stem contour from keel upwards. I created the feature f1 which is used in the curve engine for the bulb in order to give you an impression of how it works.

 

 

By controlling the position of point number 2 you can control for how long the tangent from the surface is kept. This is represented by the value Dv in the feature. By controlling the point number 3 you can control the tangent on the stem curve. This is represented by the the value Entrance Angle in the feature. As the BsplineCurve only approximates the intermediate points you won't be able to set an exact value for the beam on a certain position.

 

This setup allows you to control the beam of the bulb by using 3 options.

 

1) Modify the surface 8_fos2fwdBase: By controlling the fullness of the surface between keel and waterline, the fullness of the bulb will change accordingly.

 

2) Use the Dv value in the curve engine |curveEngines|bulb or introduce a function.

 

3) Modify the entrance angle function |basicCurves|bulbangle|fwdAngle: The y value of this curve represents the length of the bulb surface from keel to end. The x value represents the angle value*100.

 

 

I hope this helps.

 

Best regards

 

Matthias

 

supplyVessel.fdb

[Guest Mr. TAU SENG ANG__0004]

Dear Matthias Maasch,

 

thank you for the reply. I would like to confirm with you for the axis in the second image, is it in the Z-X axis?

 

The other thing i would like to confirm is that for the third option "Modify the entrance angle function |basicCurves|bulbangle|fwdAngle", am i changing the angle or the volume distribution of the bulbous bow? 

If i am changing the angle of the bulbous bow, i would like to know which angle am i changing?

[Matthias Maasch 21]

Hi Tau Seng Ang,

 

 

I would like to confirm with you for the axis in the second image, is it in the Z-X axis?

 

No, it is the Z - (X,Y) plane. Red axis = X and green axis = Y.

 

 

The other thing i would like to confirm is that for the third option "Modify the entrance angle function |basicCurves|bulbangle|fwdAngle", am i changing the angle or the volume distribution of the bulbous bow?

 

Actually you are changing both. As the bulbous bow is generated by a single BSlineCurve section, changing the entrance angle automatically changes the volume as you move the second intermediate point of the curve.

 

 

If i am changing the angle of the bulbous bow, i would like to know which angle am i changing?

 

Please have a look to the first picture in my last post again. The function |basicCurves|bulbangle|fwdAngle defines the position of the point 3. As point 4 is fixed (as a vector on your stem curve) the entrance angle into the stem curve changes when you move point 3. In order to understand how it works please change values in the feature f1 which you can find in the project file attached to my last post.

 

Best Regards

 

Matthias