# Tag Info

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After some searches I found this little paper. I will give only a short answer to the question, for details you can read the paper. So, according to the results obtained for the model in the paper: the flame length: increases as the gravity level increases from $0g_e$ to $3g_e$ decreases from $3g_e$ to $60g_e$ and blows off at higher gravity levels ...

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The pressure drop shown in the pipe in situation 2 is based on an assumed flow rate, but that flow rate can't be achieved when the pressure is only 50 Pa. You cannot deliver a fixed flow rate and a fixed static pressure: when the flow rate is kept constant, like produced by volumetric pumps, the pressure will vary with resistance: if you block the exit the ...

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I think it depends on what your friend means by "with respect to the water" When I hear that I think spatially. sample constants: you travel 1 meter per stroke, 1 second per stroke, water traveling 1 meter per second. When swimming downstream you'll cover 2 meters with respect to the ground in 1 second (yay for triathlons that are downstream). However, ...

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In my judgment, this problem was not quite interpreted correctly by the OP, and by the member who provided the answer. This seems to me to be mainly an "oscillating manometer" problem. The fluid in tank A oscillates up and down, out of phase with the fluid in tank B, which also oscillates up and down. Fluid flows periodically back and forth between tanks ...

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UPDATED ANSWER Sorry, I interpreted your question too narrowly. Couette flow occurs without a pressure gradient, due to viscous drag from a boundary surface, and is laminar. If the drag force is increased the flow can become turbulent. If a transient inertial flow begins laminar I think it must remain laminar as it dies out, because the speed of flow ...

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For a candle flame, following processes occur. 1. heat transfer (from flame to surrounding and to candle) 2. material transfer (wax vapor diffused outwards and oxygen diffused inwards) 3. heat generation (chemical reaction at stoichiometric mixture location) with gravity, the above will shift due to free convection flow. This will accelerate heat transfer, ...

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A bit of 1, a bit of 3... The technical name is flow velocity, as correctly stated in the Wikipedia article about NS equations. But one could ask what "flow velocity" means. From the Wikipedia article: flow velocity [...] is a vector field which is used to mathematically describe the motion of a continuum. Although correct, this definition is ...

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You are correct, it is the velocity of a small volume of fluid centered at the point, that is a macroscopic motion, but it is also the result of the average velocity of the particles in that volume.

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My understanding is as follows. Fluid passing the leading edge nearest to the surface is slowed by viscous forces between the surface of the body and the free stream. Adjacent layers of fluid in the stream consequently move relative to this reduced flow, and are hence affected by viscous forces themselves. The result is that the adjacent layers of fluid ...

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Huh, people? :-) He says the main tank is closed! That means it can be pressurised, and the pressure will ofc push out water, depending on pump efficiency. Nothing else needed than a valve that hinders the water from flowing back to the open reservoir when the pump is off. In the pic below a self-adjusting system. - If there is too little water in the ...

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You'll find the whole analysis in the book of Landau and Lifszyc, Hydrodynamics. This is a complicated theoretical subject which you analyze with a model of flammable gasous mixture in a cylinder tube. First you analyze how flaming surface moves in a tube and then you impose, that the whole gas is moving. Then you make this gas fell out of this tube and you ...

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Another suggestion: close valve 1 and 2 and turn on pump to make 'fountain' effect. Close valve 1 and open valve 2 and turn on pump to transfer water from reservoir to tank. Close valve 2, open valve 1 and turn off pump, to transfer water from tank to reservoir.

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The answer is no, simply because the pressure on the check valve on the side of the open pond must be greater than that within the main tank before the valve can open and let water flow from the open pond and the main tank. This will only happen if either: The open pond's water level is higher than that of the open tank; as drawn, the system will simply ...

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@phillip_0008 Pretty sure this one would work! Basically, no need for valve 3. And wouldn't be able to access valve 2. So split pump inlet between bottom of tank and bottom of reservoir, directly outlet to fountain. Water coming out of fountain sits in reservoir until it gets sucked back in thru pump. makes sense in my mind but let me know if you see ...

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How about: open valve 2 to transfer water from the reseroir to the tank. Close valve 2 to create the 'fountain' feature. Open valve 3 to transfer water from tank to reservoir.

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The water level in the pond must be the same as in the tank, so: :-)

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The gas remaining inside the tank, to a good approximation, expands adiabatically and reversibly as it expels the gas ahead of it through the valve. So you can use your adiabatic expansion equation for the gas remaining in the tank, provided the lower pressure in your equation is equal to the current pressure in the tank, and the higher pressure is equal to ...

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The usual steady state Bernoulli equation does not correctly describe the effect of the area ratio a/A (where a is the hole area and A is the tank cross sectional area) on the effluent velocity. This is because the Bernoulli equation applies only to steady state flow, and the flow in this system is transient. Because the level of fluid is changing, the ...

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You are completely correct in your statement. Usually we are only 'allowed' to use bernoulli if ${s\over\Sigma}\ll1$ such that ${v_{surface}\over v_{out}}\ll1$. This is known as a quasi-steady state approximation in which the surface velocity is so small compared to the outflow that the surface may be considered approximately static such that: {\partial v_{...

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"Correct or not" is a bit too black and white. The art of physics is often to know when a certain approximation is good enough for practical purposes. In the case that $\Sigma=s$, i.e., your tank is actually a vertical tube that is open on both sides, the Bernoulli approach is probably not the way to go. You should therefore look at the time scales. The ...

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The evolution of systems in the Hamiltonian formalism is called a flow, not because it can be described by a mapping, but because it is described by a particular mapping: one whose evolution in (q,p)-space resembles fluid flow. This resemblance gives rise to Liouville's theorem, where the Hamiltonian flow, like certain fluid flows, is shown to be ...

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