Fluids Bernoulli and a pressure field

In summary, the conversation discusses a fluid pressure balance for a cylindrical shape, where the linearized Bernoulli equation is used to determine the pressure field. The equation includes the velocity vector and a static pressure term, which is required to maintain the fluid's static interface shape. However, gravity and kinetic energy are neglected. The question is how the transient quantity of pressure is related to the static pressure term. The conversation also mentions a volume of liquid in the shape of a cylinder with a wire running through it, and how it resonates when disturbed. Despite some clarification, the listener is still unsure about the equations and their connection to the problem.
  • #1
member 428835
I have a text that writes a pressure balance for a cylindrical shape of fluid, where the linearized Bernoulli gives the pressure field ##p = p_0+\rho\partial_t \phi : \vec{v} = -\nabla \phi## where ##\vec{v}## is the velocity vector. ##p_0## is the static pressure required to maintain the fluid's static interface shape.

Evidently gravity and kinetic energy are neglected. My question is, how is it simply ##p## equates to both the transient and ##p_0## quantity? Wouldn't there have to be a transient quantity corresponding to ##p## (wherever it's located?)
 
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  • #2
joshmccraney said:
p0 is the static pressure required to maintain the fluid's static interface shape.

Could you explain that to me please ?
 
  • #3
Nidum said:
Could you explain that to me please ?
There is a volume of liquid shaped as a cylinder, and a wire runs streamwise, attaching tangentially to the volume of liquid. The surrounding media is a fluid with negligible density compared to the cylindrical liquid. In equilibrium the liquids shape will be pure cylindrical. Disturb the volume slightly and it will start to resonate and note always be cylindrical (the cross-sectional circles won't be circles, but have small waves). Given this, is my post #1 clear now?
 
  • #4
joshmccraney said:
Given this, is my post #1 clear now?

Sorry but I still don't entirely understand what you are doing . I can see now what the general idea of the problem is but I can't link that to your equations or the related question .

I'll let this one go I think . Thank you anyway for replying .
 
Last edited:

Related to Fluids Bernoulli and a pressure field

What is Bernoulli's principle?

Bernoulli's principle states that the faster a fluid (such as air or water) moves, the lower its pressure will be. Conversely, the slower a fluid moves, the higher its pressure will be. This is due to the conservation of energy in a fluid system.

How is Bernoulli's equation used in fluid mechanics?

Bernoulli's equation is used to calculate the pressure, velocity, and elevation of a fluid at different points in a system. It is commonly used in aerodynamics and hydrodynamics to analyze the flow of fluids, such as air and water, over objects.

What is a pressure field?

A pressure field is a visual representation of the pressure distribution within a fluid system. It shows how the pressure changes at different points in the system and can be used to analyze the behavior of fluids.

How is the Bernoulli effect used in everyday life?

The Bernoulli effect is used in many everyday applications, such as in the design of airplane wings and car spoilers. It is also used in ventilation systems, where the flow of air is controlled to maintain a comfortable environment. Additionally, the Bernoulli effect is used in medical devices, such as nebulizers and inhalers, to deliver medication to the lungs.

What are some limitations of Bernoulli's principle?

Bernoulli's principle assumes that the fluid is non-viscous (frictionless) and incompressible. In reality, all fluids have some level of viscosity and can be compressed to some extent. This means that Bernoulli's principle may not accurately predict the behavior of fluids in certain situations, such as when dealing with highly viscous fluids or at high speeds.

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