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myv65 · 08-01-2002, 01:56 PM

You can make water swirl with the right design, no question. Though it's off-track, I'm going to comment about your lawn-sprinkler note. This essentially comes down to a conservation of momentum. You bring water up into a chamber that has radial arms and then direct the arms such that the "jet" exits opposite the direction you wish the arms to spin. The reaction force imposed on the arms by the water as the arms redirect the water causes them to spin. This is purely a function of where the water comes in and where the water leaves (vector qualities).

Per your diagram, your block would try to spin. This is not necessarily because (or would not necessarily cause) a swirl exists. It's simply a question of where water enters and exits. It won't spin, of course, because it's held in place.

You say the diagram isn't to scale. Fair enough, I'll not try to guess whether or not it'll do what you wish. I will say that simply making the exits 1/2 the area of the entrance is probably not wise. Yeah, that'll force the average velocity to be the same in each, but it'll also reduce your flow. In hydraulics, orifice loss is not linear with area. Two ports of equal size that total the same area as a larger port will have a higher net flow loss. So long as the geometry and piping are symmetrical, flow will be relatively balanced between the exits. I would recommend they each be at least 2/3 the area of the entrance.

08-01-2002, 01:56 PM	#93
myv65 Cooling Savant Join Date: May 2002 Location: home Posts: 365	You can make water swirl with the right design, no question. Though it's off-track, I'm going to comment about your lawn-sprinkler note. This essentially comes down to a conservation of momentum. You bring water up into a chamber that has radial arms and then direct the arms such that the "jet" exits opposite the direction you wish the arms to spin. The reaction force imposed on the arms by the water as the arms redirect the water causes them to spin. This is purely a function of where the water comes in and where the water leaves (vector qualities). Per your diagram, your block would try to spin. This is not necessarily because (or would not necessarily cause) a swirl exists. It's simply a question of where water enters and exits. It won't spin, of course, because it's held in place. You say the diagram isn't to scale. Fair enough, I'll not try to guess whether or not it'll do what you wish. I will say that simply making the exits 1/2 the area of the entrance is probably not wise. Yeah, that'll force the average velocity to be the same in each, but it'll also reduce your flow. In hydraulics, orifice loss is not linear with area. Two ports of equal size that total the same area as a larger port will have a higher net flow loss. So long as the geometry and piping are symmetrical, flow will be relatively balanced between the exits. I would recommend they each be at least 2/3 the area of the entrance.