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Vertical Vessel

OLUBUKOLAADEBOY
8-Gravel

Vertical Vessel

Good Afternoon Everyone,

Attached is copy of MathCAD worksheet on vertical vessel. The total height of the vessel is 72 ft. The skirt height is 18.333 ft. In the worksheet L is defined as the length of each section of the profile and z is the elevation from the base of the vessel. The function L has a negative number and z should sum up to 72 ft at the top of the vessel. Please I'm getting a strange number in L of -1.33 and z is reporting 73 ft and 72 ft. Would anybody who is good in programming help.

Regards,

Boyer

12 REPLIES 12

1. It will be better use for your problem not ceil but Ceil function. The Ceil function works with units - see the picture.

2. It will be good to have not only a program but the description!

Ceil.png

Has this problem been solved?

Mike

Good Morning Mike,

The answer is No, I'm still having problem. Please see if you can help.

Regards,

Boyer

see attached

Good Afternoon Wayne,

Thanks for your help. How can I change the code such that, when a different skirt height is input the worksheet work without an error?. Please guide me.

Regards

Olubukola,

The revised function I provided was based on the variable h.skirt.

I don't know how you decide what section heights to use (though I see what you did in the programs); however I would provide that criteria as input also, unless it never changes.

However, normally when I write a standard calculation like you have, I assign an argument list and include every variable used in the function in the argument list. That way I can reuse the functions in the same file for different designs, do studies with respect to the variables or whatever.

Actually, if something is going to be used for many designs, I will then put all the functions in a separate file and just reference that file into the working file. That way if you refine or change (or correct something) it will be reflected in all designs. (of course, if a correction, you would need to go back and review the previous designs). As a further note, as the standard designs evolve, the newer versions may not work in the previous designs so keep copies of previous versions of the referenced files.

I added an argument list to the function for L() as an example.

See help "Including One Worksheet Inside Another" for Reverenced Files

Good Afternoon Wayne,

I noticed that in the file you send the z values is given an error in MathCAD stating that "invalid array index", Please how do you fix this error.

Regards,

Boyer

Boyer,

I did not follow all the the way through, but here is some more with and example of returning values (zbtm and arm) from the program with a nested matrix.

Again, if you l prefer, you can drop the argument lists.

Good Afternoon Wayne,

The argument list, is a better way. When I tried to substitute z to zbmt in Kz, I still get an error. Please guide me through. My goal is to get the total horizontal force and overturning moment at the base of the vessel.

Regards,

Boyer

Boyer,
I normally approach it a little differently,

see attached

Good Afternnoon Wayne,

Thanks, for your help. I will take a good look at your approach.

Have great week-end.

Boyer

In you program to determine n, you have assumed a 15' skert, but then you have set the h.skert to 18.33', so the calclation for n is too large.

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