# Free Jets

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 November 4, 2007, 16:23 Free Jets #1 Valerio Guest   Posts: n/a What are the best boundary conditions type on simulating free jets???

 November 5, 2007, 12:40 Re: Free Jets #2 Valerio Guest   Posts: n/a i'm trying with simmetry on all domain boundaries...is it right???

 November 7, 2007, 04:39 Re: Free Jets #3 Adrian Lai Guest   Posts: n/a I've tried a single free water jet into a stagnant water body, do u mean this by 'free jet'? Adrian

 November 7, 2007, 11:32 Re: Free Jets #4 Valerio Guest   Posts: n/a yes. Free Jets for jets in the same fluid (ex: water in water) instead free sufarce for jets in different fluids (for example water in air). Actually i'm trying the simulation in a cavity with walls sufficiently far from fluid inlet. In other words i'm trying on reproducing real conditions.

 November 7, 2007, 11:39 Re: Free Jets #5 Adrian Lai Guest   Posts: n/a Pressure outlet boundary condition at the outlet; Wall boundary condition would be okay if the jet is sufficiently far away from the boundaries; velocity inlet at the jet nozzle. Finer mesh required near the jet. Right now I need to run it as unsteady case (til it becomes quesi-steady), not sure whether anyone has done it using steady calculation with success. Adrian

 November 8, 2007, 12:01 Re: Free Jets #6 Valerio Guest   Posts: n/a I know! However i already studied flow field inside another device and now i'm using calculation at outlet like new problem's boundary conditions for external field simulation. Flow field is not very easy...i have not a classic submerged jet but 3d swirling jet. To peform a complete simulation of internal flow and external jet in unsteady state is not very very easy because inside the device the flow is compressible but the highly deceleration conduce the fluid at outlet at incompressible velocities so that i can simplify my simulation. And i will be (with a complete simulation) a too much big domain.

 November 8, 2007, 12:04 Re: Free Jets #7 Valerio Guest   Posts: n/a i have another question... in unsteady state simulation i would to obtain a graphic of pressure versus position along a particular line in time. is it possible define a fixed scale in XY plot, in same way???

 April 8, 2010, 15:14 Re no. relation for Jet #8 New Member   Join Date: Mar 2010 Posts: 7 Rep Power: 8 I think this is the best place where I can ask my question. I am wondering what is range for Reynolds number (Re) for a single jet. That means laminar single jet flow is condition up to what 'Re' number. From which 'Re' number, turbulent flow condition starts. Also, when is incompressible flow valid for single jet?

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