Hi all,

I am doing a nozzle modeling. The nozzle node is in -Z direction in CAESAR. What would be centerline direction cosines for this nozzle to use WRC 107 analysis?

Thanks,

0, 0, -1

Thanks Richard.

For vessel vector, is it always 0,1,0?

If nozzle is in -X direction, so the nozzle vector should be -1,0,0 and 1,0,0 for nozzle in +X direction. Is this right?

If the nozzle is on the bottome vessel head, what would be vectors for nozzle and vessel?

You must try to understand the geometry and coordinates of your system.


Best regards
Marian

I am acturally very confused now about how to convert the CAESAR coordinates to WRC 107 coordinates. Any advice on this is very appreciated.

Thanks,

You have your global XYZ directions, which you can visualize with the CAESAR II graphics (look at the compass in the lower left hand corner). Direction cosines line up with this axis system:

( X, Y, Z )
( 1, 0, 0 ) is horizontal in the X direction
( 0, 1, 0 ) is vertical in the Y direction
( 0, 0, 1 ) is horizontal in the Z direction

How to put the vessel and nozzle vectors if the nozzle is on the vessel head?

Read these earlier posts, all found using the [Search] function:


http://www.coade.com/ubbthreads/ubbthrea...ch=true#Post767

http://www.coade.com/ubbthreads/ubbthrea...=true#Post17320

http://www.coade.com/ubbthreads/ubbthrea...=true#Post10525

Currently myself is using Caesar2 Release 5.1. The co ordinate system icon, when it is viewed from the top has the Positive(+) X-axis going towards the left (towards west). The positive part of the Z-axis going upwards (towards north. The CAD drafting tools like Auto cad etc have the positive X-axis set towards the east direction. Is there any specific reason for Caesar2 having the positive x direction towards left. Why not it match with the common cad tools. This will help comparing the Cad models easly with the CAESAR II model. This together with the WRC coordinates or API610 co ordinates creates mis understanding. Any response!

CAESAR II uses the typical "right hand" coordinate system. So take your right hand and extend the first three fingers (counting the thumb as a finger) so they are all mutually perpendicular, and look at your palm.

Your index finger should be pointing up, which is the CAESAR II "Y" axis. The thumb should point to your right shoulder, this is the CAESAR II "X" axis. The middle finger should point to your left shoulder, this is the CAESAR II "Z" axis. If the CAESAR II graphics show anything else, then the model has been (manually) rotated.

Thank you for your response. But my question is slightly different. Without doing any modeling in caesar2, in the first blank screen, if we see the top view by clicking on the icon for top view, the X-axis arrow is towards the left (west direction). If we enter a positive x length for pipe the pipe will go in the left direction. In other words if the pipe to be routed in the east direction we have to give negative x values. At the same time the Z-direction is towards north and Y is vertical up. If we go for the icon for bottom view the X is in east direction and Y-is in the vertical downward direction and Z- is in the north direction. With special execution parameters menu if we change the Z-axis to vertical, the positive X direction and positive Y direction goes towards west and south respectively. In the 4.1, 4.2 versions of Caesar I never noticed this. Or am I wrong!!
Also Coade may include some example files for WRC107/297, API610 etc. Some complete examples may be included in the user manuals also with adequate sketches. Most of the common analysis we do are for pump nozzles, and other equipment nozzles.

We have changed this behavior for Version 5.20 (soon to be released).