Again. I'm new to Ceasar
I was very surprised to see the way that Ceasar defines wave/current direction.
The cosines method it uses is different than any of the codes or other software I use.
It is not how ANSYS, ORCAFLEX or Ariane8 defines direction. But fine...every software is different and this is acceptable.
However, before using a wave or current in my model I ran a test with an single length of pipe along the x-axis with one node anchored.
Then ran wave and current only load cases in multiple directions (varying cosines). I assumed that Ceasar considers "Y" to be vertical (that seems to be the case). So, I expected that varying the cosines would result in varying x and z reactions in proportions that indicated the applied direction.
To my surprise I was only getting a varying "z" reaction and zero "x" reaction for all directions. It seems like (i could be wrong) that Cd is a the normal drag coefficient and there is NO axial drag coefficient.
OMG no axial drag or axial added mass!!!!! Only lift and normal??? How can this be. So a I rotated the model and tested. Again, a single pipe is not taking wave or current load from load components axial to the pipe.
Is this an oversight? I don't often do piping, but from all my years of offshore engineering for structures and mooring systems I know that axial wave and current load can be significant and should not be ignored.
Further more, if hand calculations are performed for comparison to Ceasar results, how could they be expected to tally if axial wave and current load is not considered?
I see a normal drag coefficient and a lift coefficient, but where is the axial drag coefficient?
Also, no axial added mass?????
Imagine a short length of large diameter pipe end with a blind flange for example. That could present a significant axial area. Hand calc the drag and added mass loads and anyone can see that they should not be ignored. Specially if buckling is a consideration. This just seems deeply strange to me...I must be missing something... my input must be wrong.
Such a popular software could not be missing such things.
How do I get Ceasar to consider axial hydrodynamic loads?
I was very surprised to see the way that Ceasar defines wave/current direction.
The cosines method it uses is different than any of the codes or other software I use.
It is not how ANSYS, ORCAFLEX or Ariane8 defines direction. But fine...every software is different and this is acceptable.
However, before using a wave or current in my model I ran a test with an single length of pipe along the x-axis with one node anchored.
Then ran wave and current only load cases in multiple directions (varying cosines). I assumed that Ceasar considers "Y" to be vertical (that seems to be the case). So, I expected that varying the cosines would result in varying x and z reactions in proportions that indicated the applied direction.
To my surprise I was only getting a varying "z" reaction and zero "x" reaction for all directions. It seems like (i could be wrong) that Cd is a the normal drag coefficient and there is NO axial drag coefficient.
OMG no axial drag or axial added mass!!!!! Only lift and normal??? How can this be. So a I rotated the model and tested. Again, a single pipe is not taking wave or current load from load components axial to the pipe.
Is this an oversight? I don't often do piping, but from all my years of offshore engineering for structures and mooring systems I know that axial wave and current load can be significant and should not be ignored.
Further more, if hand calculations are performed for comparison to Ceasar results, how could they be expected to tally if axial wave and current load is not considered?
I see a normal drag coefficient and a lift coefficient, but where is the axial drag coefficient?
Also, no axial added mass?????
Imagine a short length of large diameter pipe end with a blind flange for example. That could present a significant axial area. Hand calc the drag and added mass loads and anyone can see that they should not be ignored. Specially if buckling is a consideration. This just seems deeply strange to me...I must be missing something... my input must be wrong.
Such a popular software could not be missing such things.
How do I get Ceasar to consider axial hydrodynamic loads?
