Hydraulic Transmision

Fiedde1887 · August 2, 2016, 08:14

Hello everybody,

i am simulating a hydraulic transmition with two Pistons. The first Piston move down with a constant Speed (Tools-Motion-Translation) and the secound Piston get the answer by the fluid with a DFBI-Motion and should move up. I want to simulate it with a fluid which contained a constant density like water ore oil. The Motion is realised with an overset mesh and the physics work with a combresible, ideal gas.
But, when i try a incombresible fluid, the Simulation blows my Piston through the Roof of my Office

So, i want to ask you, if anyone calculated a similar case? It´s a very simple configuration, so i wonder, why it react like that.

Thank you in advance
Nils

Fiedde1887 · August 2, 2016, 10:42

Okay, i get a solution for my Problem. I chosed the Option "User defined EOS" under Fluid Models insted of Constant density. And it works with the Option compressible aktivated and "Density pressure Derivate" set by 0

August 2, 2016, 08:14	Hydraulic Transmision	#1
Fiedde1887 Member Nils Hennig Join Date: Apr 2015 Posts: 44 Rep Power: 11	Hello everybody, i am simulating a hydraulic transmition with two Pistons. The first Piston move down with a constant Speed (Tools-Motion-Translation) and the secound Piston get the answer by the fluid with a DFBI-Motion and should move up. I want to simulate it with a fluid which contained a constant density like water ore oil. The Motion is realised with an overset mesh and the physics work with a combresible, ideal gas. But, when i try a incombresible fluid, the Simulation blows my Piston through the Roof of my Office So, i want to ask you, if anyone calculated a similar case? It´s a very simple configuration, so i wonder, why it react like that. Thank you in advance Nils

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August 2, 2016, 10:42		#2
Fiedde1887 Member Nils Hennig Join Date: Apr 2015 Posts: 44 Rep Power: 11	Okay, i get a solution for my Problem. I chosed the Option "User defined EOS" under Fluid Models insted of Constant density. And it works with the Option compressible aktivated and "Density pressure Derivate" set by 0