Hello,
I am using digital DATCOM to obtain aerodynamic data for a launch vehicle configuration. I have read the 2011 revision of the documentation found here: https://pdfs.semanticscholar.org/0190/147a0905ea452d7fa36d0d663044aa5f460a.pdf
My question is, to people who are familiar to the software: is it possible to run an analysis on a vehicle with multiple bodies? An example is the VEGA launch vehicle. It has a different diameter for the second stage, first stage, and payload fairing. Whats more, is that I want to be able to model the interstages.
I have seen examples and options in the manual for diameters of the aft and main body, which would mean only 2 different diameters of the entire body. Any idea how I can accomplish this, or if it is even possible?
This is a limitation of the methods used within the code. You can use option 2 of axibod to define the vehicle more precisely, but should also enter option 1 values that best approximate the shape.
There is a 2014 version of the code -- the difference is in improved body vortex shedding and supersonic nose drag. Still no multibodies.
If you need higher fidelity, I suggest CFD. I usually use CART3D (inviscid CFD), but that is only for US use.
( By the way, Digital DATCOM refers to the digital version of the original DATCOM set of data, which was for aircraft. Missile DATCOM is a different program. Maybe only old folks know this.)
@Janet M. Ross Thank you for the reply. Do you know if this is possible in missile DATCOM, or are there also multibody limitations for that?
No, it isn't possible in Missile DATCOM -- sorry if I confused you with the reference to digital DATCOM, which is for aircraft.
You should use option2 axibod and also add an approximation of option1 inputs.
You can use option2, where you input all the diameters, and you are not limited to the option1 constraints. This is fine for hypersonic Machs. To get a reasonable answer at lower Machs, also enter the approximation using option1.