Hi Guan,
well, the architecture of Chrono allows the solution of custom DAEs, but
it requires that you go through a very complex process of inheriting
from ChPhysicsItem c++ classes and that you override lot of member
functions (after some manipulation of your DAEs so that you can write
them in semi explicit form), etc. etc. Shortly: I would not reccomend
this. Maybe in future we'll implement some sort of "easy base-class for
custom DAEs equations" where one just have to implement a lambda or a
callback for the function evaluation and constraint evaluation, plus few
minimal other things, but it is not planned in the short term.
As a workaround, I'd suggest you to do some cosimulation, as Dan suggested.
Alessandro
On 09/06/2022 22:00, 'Dan Negrut' via ProjectChrono wrote:
Guan – you cannot append a simple DAE system example (e.g. 3 equation
with 3 unknowns) to Chrono and have it solved.
You should define a Chrono model that will lead to those DAE equations.
One way to go about it, is to run a cosimulation, say with Matlab or
Python. You define your equations, you solve them, and during the
solution process you can talk with Chrono. In this sense, Chrono is
not like Modelica. I’m not a Modelica user, so perhaps Alessandro
Tasora, if he reads this, might provide a better answer than mine…
Dan
-------------------------------------------------
Bernard A. and Frances M. Weideman Professor
NVIDIA CUDA Fellow
Director, Wisconsin Applied Computing Center
Department of Mechanical Engineering
Department of Computer Science
University of Wisconsin - Madison
4150ME, 1513 University Avenue
Madison, WI 53706-1572
608 772 0914
http://sbel.wisc.edu/ <http://sbel.wisc.edu/>
http://projectchrono.org/ <http://projectchrono.org/>
-------------------------------------------------
*From:* [email protected]
<[email protected]> *On Behalf Of *Guan Yu
*Sent:* Wednesday, June 8, 2022 8:29 PM
*To:* ProjectChrono <[email protected]>
*Subject:* Re: [chrono] Discrete/Continuous hybrid DAE system
Hi Dan,
Thank you very much for your reply!
I will go trough the materials you sent me.
Another question I am currently have is that if I would like to build
a simple DAE system example(e.g. 3 equation with 3 unknowns) using the
HHT solver in Chrono Engine, is there any example code I can learn or
any guide that I could follow?
Thank you in advance!
Best,
Yu
在2022年6月7日星期二 UTC+8 22:49:59<Dan Negrut> 写道：
Hi Yu - If you are interested in sloshing and simulating that in
Chrono, see this contribution:
https://www.sae.org/publications/technical-papers/content/2018-01-1110/
It’s not simple, but it can be done. You need to have knowledge
of CFD, not a stroll in the park.
Alternatively, you can use DualSPHysics, that is interfaced to
Chrono and is strong on the CFD side of things – see
https://dual.sphysics.org/ .
Good luck!
Dan
-------------------------------------------------
Bernard A. and Frances M. Weideman Professor
NVIDIA CUDA Fellow
Director, Wisconsin Applied Computing Center
Department of Mechanical Engineering
Department of Computer Science
University of Wisconsin - Madison
4150ME, 1513 University Avenue
Madison, WI 53706-1572
608 772 0914 <tel:(608)%20772-0914>
http://sbel.wisc.edu/ <http://sbel.wisc.edu/>
http://projectchrono.org/ <http://projectchrono.org/>
-------------------------------------------------
*From:* [email protected] <[email protected]>
*On Behalf Of *Guan Yu
*Sent:* Tuesday, June 7, 2022 5:43 AM
*To:* ProjectChrono <[email protected]>
*Subject:* [chrono] Discrete/Continuous hybrid DAE system
Hi there,
I just started learning ProjectChrono and I am trying to build a
rocket launch simulation that contains multiple sub-systems such
as a liquid rocket engine system, control system, etc.
I believe that ProjectChrono will perfectly get the multi-body
part done, but I have the following question:
I had successfully modeled the engine system as a 1D fluid system
using OpenModelica(a Modelica software that could solve
custom-build DAE system), the model ends up to be a
discrete/continuous hybrid DAE system (has around 500 constrain
equations that solving 500 variables in which there might be 50
state variables) that solved by DASSL solver.
I know it seems odd to solve an 1D fuild system in multi-body
solver, however technically speaking, is it possible that I could
rebuild this 1D fluid DAE system using ChronoEngine?
If so, which Chrono module(s) or built-in solver(s) should I use?
Thank you a lot in advance!
best,
Yu
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