This rollout controls the fluids motion parameters.


Simulator Panel

Inertial forces (MXS: ext_wind) - when checked moving the simulator's box causes inertial forces in the opposite direction of the movement. It can be used for fireballs, liquid containers, and any situation where we need to avoid the moving geometry replacing it with moving air or liquid around it. When this option is used with the initial fill up option and open boundary conditions, a simulation of moving object over a sea surface can be done.


Moving container of water with Inertial forces option enabled




Std. gravity (MXS: grav, gmul) - when checked a standard gravity of 9.8 m/s^2 is automatically added. This value is a multiplier.


Time scale (MXS: timescale) - time multiplier. Can be used for slow motion effects.

Vorticity (MXS: vorticity,velvort) - The grid based simulations tend to dissipate all the content of the grid at each step, and this includes the velocity too. When the velocity dissipates, the small scale turbulences are suppressed, and without additional help the simulation becomes very smooth and laminar. This parameter controls a simulation stage that accelerates the small scale vortices, keeping them from disappearing. This process can't compensate the dissipation perfectly, but helps a lot. The xV check box modifies the process in order to prevent the over compensating in the slower areas.


Vorticity=0 Vorticity=0.2

Cooling (MXS: cooling) - this parameter controls the cooling of the fluid due to radiation. Value of 1 corresponds approximately to a real smoke with half thickness of 4m. The real cooling is a very complicated process similar to the Global illumination rendering, so here a simplified formula is used.


Smoke buoyancy (MXS: smoke_bcy ) - the buoyancy of the smoke. Positive values make the smoke move upwards. Negative values make it move downwards.


Fuel buoyancy (MXS: fuel_bcy) - specifies the buoyancy of the fuel.




The options in this rollout allow the user to add random fluctuations in the fluid dynamics. It works in combination with the Vorticity parameter.


Amount (MXS: rand) - the amount of the randomization.


Dynamics (MXS: rndfrq) - the speed of change of the fluctuations.