41 Cistern Program

[wojtek]

(08-11-2016 12:46 PM)SlideRule Wrote:  Does anyone have the program listing (key-codes etc.) for the CISTERN program described in the 13 April 1992 edition of Oil & Gas Journal article Simple Program Calculates Partial Liquid Volumes in Vessels? The program listing was available by request to anyone asking with a no-later-than date of 30 July 1992.

Firstly sorry for typos, I am lying on a hospital bed and use my smartphone.
I don't have this journal, but perhaps this can be of help to you. If I understood your problem cerrectly you would like to know a partial volume of liquid in a cy
lindrical vessel set horizontally on the ground, given the depth of liquid in the vessel. I am rather weak at math but after a short search of the internet I found a formula for this problem. Details are on the picture attached. So, given the R and L (radius and lenght of the cistern respectively) and H (measured depth of liquid) the program for 50g could be something like:

<< -> H << Pi R 2 ^ * 1 H R / - acos * 180 / R H - H R 2 * * H 2 ^ - sqrt * - L * 2 / ->num >> >>
Original formula had no division by 2 at the end and gave wrong results for the full and half full vessel. Addind this division by 2 gives correct results for H=0, R and 2R.
Hope to help a little
PS. 50g should be in degree mode, H is on the stack, R and L in global variables.
PS2. The formula is for circular cross-section, for other shapes, eliptical for example would be more complicated