# Pressure and velocity relationship in fluids allowed

### What is Bernoulli's equation? (article) | Khan Academy

For turbulent flow, the speed and or the direction of the flow varies. equation does, relating the pressure, velocity, and height of a fluid at one. When fluid is passing through the pipe having constant area of cross section Pressure and velocity have an inverse relation an example pumps are used to to . It is a known fact that as the velocity of a fluid increases the pressure behind this Inverse relation between Pressure and Velocity in the Fluid Flow. . it is an active discussion over a topic which allows to see a problem with.

### What is the relationship between pressure and velocity for a liquid and gas? | How Things Fly

And I very well understand the difference between Compressible and Incompressible flow concepts. And I am strictly speaking about the Incompresible flows in liquids.

If you increase the fill rate the level in the bucket goes up, and passes the outflow rate. Pressure at the outlet is determined by the surface area of the water in the bucket, the higher it goes the higher the outflow rate.

### Pressure - Velocity relation in fluids | CrazyEngineers

Flow pressure at the hole equals surface pressure cross-section of container. The pressure of water at any level would simply be the Height of Water Column, and the pressure is same for the same height and is equally tramsmitted in all directions this the beauty of hydraulics. The forces normal to the inner surface of the bucket, all pointing inwards, 'react' to the pressure by 'expelling' water from the hole.

Flow out of the hole is the water 'reacting' to these forces. And the Outflow rate is not the function of surface area, but simply the height of the water column above the hole. Higher the water column higher the pressure.

It is only the pressure acting at the particular height which causes the water to flow out as soon as it finds an opening and the constrain is removed the hole in this case. There is nothing as reacting to the forces, the pressure is equal in ALL directions it is not unidirectional as any other stresses are, thats Pascals Law.

Shear is not constant in fluids, e. Shear in laminar flows is linear, relative to vortical flow which isn't I have never said that the shear is constant. And yes you are right, shear does exsist between the layers of water in a Vortex flow too. Stress at the inside walls of the container is "absorbed" into shear by the fluid motion.

Flow is slower at the edges, because there is more friction and interaction, the flow is almost linear near the center, less linear near the walls. It is correct that the flow is slower at the edges due to friction between the fluid molecules in immediate contact with the surface, and this is exactly what causes the VELOCITY PROFILE in the fluid flow where the velocity is maximum at the center line of flow and lowest at the edges.

But there is nothing such as absorbing of the stresses being absorbed into shear. The flow is by the virtue of the driving force and the shear is merely the resistance to flow. The centrally-directed flow 'pulls' the outer fluid along, translating normal stress into shear velocity It is not the inner flow which pulls the outer fluid, but in fact the nature of the velocity profile is itself dictated by the friction between the outer molecules, and the velocity goes on increasing from outside to inside as the friction goes on reducing towards the centre.

Looked at in that way, the equation makes sense: For our first look at the equation, consider a fluid flowing through a horizontal pipe. The pipe is narrower at one spot than along the rest of the pipe. By applying the continuity equation, the velocity of the fluid is greater in the narrow section.

Is the pressure higher or lower in the narrow section, where the velocity increases? Your first inclination might be to say that where the velocity is greatest, the pressure is greatest, because if you stuck your hand in the flow where it's going fastest you'd feel a big force. The force does not come from the pressure there, however; it comes from your hand taking momentum away from the fluid.

The pipe is horizontal, so both points are at the same height. Bernoulli's equation can be simplified in this case to: The kinetic energy term on the right is larger than the kinetic energy term on the left, so for the equation to balance the pressure on the right must be smaller than the pressure on the left. It is this pressure difference, in fact, that causes the fluid to flow faster at the place where the pipe narrows. A geyser Consider a geyser that shoots water 25 m into the air.

How fast is the water traveling when it emerges from the ground?

## Bernoulli’s Effect – Relation between Pressure and Velocity

If the water originates in a chamber 35 m below the ground, what is the pressure there? To figure out how fast the water is moving when it comes out of the ground, we could simply use conservation of energy, and set the potential energy of the water 25 m high equal to the kinetic energy the water has when it comes out of the ground.

Another way to do it is to apply Bernoulli's equation, which amounts to the same thing as conservation of energy. Let's do it that way, just to convince ourselves that the methods are the same.

But the pressure at the two points is the same; it's atmospheric pressure at both places. We can measure the potential energy from ground level, so the potential energy term goes away on the left side, and the kinetic energy term is zero on the right hand side.

- Bernoulli's principle

This reduces the equation to: The density cancels out, leaving: This is the same equation we would have found if we'd done it using the chapter 6 conservation of energy method, and canceled out the mass. To determine the pressure 35 m below ground, which forces the water up, apply Bernoulli's equation, with point 1 being 35 m below ground, and point 2 being either at ground level, or 25 m above ground. Let's take point 2 to be 25 m above ground, which is 60 m above the chamber where the pressurized water is.

## What is Bernoulli's equation?

We can take the velocity to be zero at both points the acceleration occurs as the water rises up to ground level, coming from the difference between the chamber pressure and atmospheric pressure. The pressure on the right-hand side is atmospheric pressure, and if we measure heights from the level of the chamber, the height on the left side is zero, and on the right side is 60 m. Why curveballs curve Bernoulli's equation can be used to explain why curveballs curve.

Let's say the ball is thrown so it spins. As air flows over the ball, the seams of the ball cause the air to slow down a little on one side and speed up a little on the other. The side where the air speed is higher has lower pressure, so the ball is deflected toward that side. To throw a curveball, the rotation of the ball should be around a vertical axis.