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Let's say I have a free jet of air leaving a pipe into the atmosphere. I know that the static gauge pressure at the pipe exit is equal to the atmospheric. But what about the static gauge pressure 10 meters away if the air is still traveling as a free jet? Is it still atmospheric?

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I'm confused. Bernoulli's eqn. says the static pressure inside the jet should be less than atmospheric. As you go further out and the jet slows down, then it should approach atmospheric pressure. The pressure gradient between the atmosphere outside and the low pressure inside the jet leads to air getting sucked into the jet (entrainment).

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I'm not saying 10 meters radially across the jet. I'm asking if we put another point that is 10 meters away from the opening of the pipe (where the pressure is atmospheric) along the streamline. –  Greg Harrington Oct 28 '11 at 17:56
10 meters away, the jet should have slowed considerably, so it should be close to atmospheric pressure according to Bernoulli. –  user1631 Oct 28 '11 at 18:40
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