Sample propeller for KCS hull geometry

[Matthias Maasch 21]

Hi folks,

 

Mr. Akhil Gb posted a very interesting request in the Meta-thread: Marine - Propellers. It deals with the NMRI sample propeller for the famous KCS test case and is maybe interesting for other users of CAESES as well. Please find his post below:

 

 

Hi

As a part of my research work i am preparing ship model and propeller. KCS ship has been taken for the reference study which is readily available in internet.I am facing some problem with the propeller modelling due to lack of iges or offset files.
I have free licensed software caeses with me. And i observed that there is a 3 meter diameter propeller with NACA66 section is available in the software. I tried to scale down it to my propeller diameter which is 0.105 m with NACA66 profile.But the pitch and other datas are seemed to be different.Is there any way in which i can modify the propeller to my requirement.
Following are the requirement.
 

 r/R       P/D      Rake           Skew(¡£)    C/D         fo/C       to/D 

0.180   0.834700   0.0000     -4.720   0.231300   0.028448   0.045850 

0.250   0.891200   0.0000     -6.980   0.261800   0.029641   0.040710 

0.300   0.926900   0.0000     -7.820   0.280900   0.029477   0.037120 

0.400   0.978300   0.0000     -7.740   0.313800   0.026769   0.030470 

0.500   1.007900   0.0000     -5.560   0.340300   0.022010   0.024590 

0.600   1.013000   0.0000     -1.500   0.357300   0.017324   0.019470 

0.700   0.996700   0.0000      4.110   0.359000   0.014039   0.014920 

0.800   0.956600   0.0000     10.480   0.337600   0.011996   0.010730 

0.900   0.900600   0.0000     17.170   0.279700   0.010440   0.006930 

0.950   0.868300   0.0000     20.630   0.222500   0.010067   0.005280 

1.000   0.833100   0.0000     24.180   0.000100   8.700000   0.003690 

 

It will be a great help for my future work if you can help me out from these situation with a reference ,tutorial etc.

 

Dear Akhil,

 

yes, it is possible. The propeller modelling in CAESES is usually based on the generic blade object, which allows you to automatically connect your blade functions (skew, pitch, rake - given in the table above) with a specific profile definition based on a curve engine (with the profile functions chord, thickness, camber - given in the table above) . The result is a single blade with the radius of 1. Please start with having a look into the sample Blade Design > Maritime > Propeller Setup (which you are already refering to) and modify the functions ( baseline > 01_functions) and the blade (baseline > 00_blade > blade) according to the given table data.

 

Any further step depends on your requirements. If you need a text based output of radial profile cuts along the blade you could try to export the final propeller via File > Export > PFF. If you need a geometry export such as IGES or STL of a full propeller, you would have to take further modelling steps, e.g. using our BREP geometry. Therefore you could have a look into the sample Blade Design > Maritime > Propeller Blade and Hub Fillet.

 

Please let my know if you have any problems.

 

Best regards

 

Matthias

[Mr. akhil bg 0]

Hi Matthias,

Thanks for the reply.

Am working on it.Currently there are 5 'chords'  defined on the model. i think they are co ordinates of the propeller chords starting form hub. ie, X and Y. So i tried to add some more chords since there are 10 r/R values and corresponding chord lengths are defined in my propeller.But am unable to add any more in the given file. How to do it....?

[Matthias Maasch 21]

Hi Akhil,

 

 

i think they are co ordinates of the propeller chords starting form hub. ie, X and Y

Exactly.

 

 

So i tried to add some more chords since there are 10 r/R values and corresponding chord lengths are defined in my propeller.

Good. Simply change the values/add points to adapt it to the table for each function.

 

 

But am unable to add any more in the given file. How to do it....?

You could set up a completely new curve or adapt the existing ones. After you added all your points as 3D Points, you could drag and drop it into the pointlist of the respective curve. As it will be added at the end of the point list each time you have to move it manually to its final destination using the arrow buttons.

 

 

The other option would be to create all your points, selecting them in the right order and create a new curve via CAD > Curves > e.g. BSplineCurve.

 

I hope this solves your problems.

 

Cheers

 

Matthias

 

[Mr. Md Shahriar Nizam 0]

Hello Matthias,
To understand the propeller design procedure in CAESES, I was checking the sample propeller case. In the sample case, I can understand chord, pitch, rake and skew except maxthickness. In maxthickness I am having some problems. I have made the thickness constant but from  the 2DWindows (2DScene_propeller_01 feature) it showing different thickness instead of constant thickness.
Can you please give me a probable reason behind it?

I am attaching the file with the reply.

Thanks,

Md Shahriar Nizam 

mod-propeller.fdbc

[Mr. Claus Abt 14]

It is relative thickness, (thickness/chord).

Cheers

Claus

[Mr. mohamad gh 0]

hi freinds.          According to the above table in skew .i think  skew  values should not be in software ,But must be put ski values In the screenshot below.  is it right?

 

 

 

 

 

 

 

 

 

 

         best regards.......... 

 

          mohamad

[Matthias Maasch 21]

Hi Mohamad,

 

using the Generic Blade you can either apply skew values via distance (as a linear dimension) or via angle. When you extend the header "Radial Information" in the Object Editor you can switch the Skew Representation.

 

Cheers

 

Matthias