Timeline for Is there a mathematical formula to calculate drag force without empirical testing?
Current License: CC BY-SA 4.0
9 events
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| Sep 19, 2020 at 14:45 | comment | added | Eric Towers | @BillThePlatypus : Same advice for you as Answerer gave OP: Read the linked page. There you will find a plethora of information about the development of equational models and their incorporation into CFDs. There is even a section specifically about how certain equational models are built on top of other equational models. CL and CCL equational models are not "based off of empirical measurements of simple cases"; they are first principles derivations. | |
| Sep 18, 2020 at 23:37 | comment | added | BillThePlatypus | @HagenvonEitzen Yes, they are, but in many cases the equations (at least for ideal behavior) can be derived mathematically from some simple laws. But in some cases (drag and convection come to mind) the equations are more of a curve fit than a nice equation. | |
| Sep 18, 2020 at 20:42 | comment | added | Hagen von Eitzen | @BillThePlatypus All mathematical equations to describe physical processes are based off empirical measurements, aren't they? | |
| Sep 18, 2020 at 17:28 | comment | added | Ryan C | Note also that the process of subdividing the volume is itself a tricky art form. If you choose the wrong grid to discretize your problem, you will get weird, unphysical, incorrect behavior due to the limitations of the discrete model, like reflections and wakes from surfaces that aren't really there, but are subtly implied by the grid structure you chose. If you have to interpolate the results to a different grid needed for some reason by another part of your toolchain, things get much worse. In summary, +1 to bad CFD is easy, but good CFD is really hard. | |
| Sep 18, 2020 at 14:12 | comment | added | BillThePlatypus | I was under the impression that CFD algorithms are based off of empirical measurements of simple cases, rather than the implementation of purely mathematical equations. | |
| Sep 17, 2020 at 21:04 | comment | added | Russell Borogove | There are many references on the Wikipedia page I linked in my answer; they should keep you busy for a while. I don't know much about CFD myself. | |
| Sep 17, 2020 at 19:11 | comment | added | Xi Liu | Thanks for your response! Could you elaborate more on how the airflow is simulated within the small volume regions or simply refer me to some other resources? I am actually researching this for a school project and am exploring how we can speed up the calculation of drag force by CFD software. Do you think using quantum algorithms can help? | |
| Sep 17, 2020 at 19:04 | comment | added | Organic Marble | +1 Before you youngsters and your new-fangled computers took over there were entire books written on estimating drag (Hoerner 1965 Fluid-Dynamic Drag) | |
| Sep 17, 2020 at 18:51 | history | answered | Russell Borogove | CC BY-SA 4.0 |