What Equations Govern This Hypothetical Fluid Flow?

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SUMMARY

The discussion centers on the analysis of a hypothetical 2D inviscid, steady, uniform, and parallel potential flow characterized by the velocity vector ## \vec{v} = ##, where ##u= U[z]## and ##w= W[z]##. The author proposes using the Navier-Stokes Equations in rectangular coordinates, noting that the steady condition implies ##\partial_t = 0## and the inviscid condition indicates ##\mu = 0##. The conclusion drawn is that the equation of motion simplifies to ##\nabla ^2 \vec{v} = 0##, leading to ##\nabla^2 u = 0## and ##\nabla^2 w = 0##, which the author seeks confirmation on.

PREREQUISITES
  • Understanding of 2D fluid dynamics
  • Familiarity with Navier-Stokes Equations
  • Knowledge of potential flow theory
  • Basic concepts of vector calculus
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  • Study the derivation and applications of the Navier-Stokes Equations in fluid mechanics
  • Explore potential flow theory and its implications in inviscid flows
  • Research the mathematical techniques for solving Laplace's equation, ##\nabla^2 \phi = 0##
  • Investigate the physical interpretations of steady, uniform, and parallel flow conditions
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Fluid dynamics students, researchers in theoretical physics, and engineers working on inviscid flow problems will benefit from this discussion.

member 428835
Hi PF!

I was reading lecture notes from a university and I stumbled on this situation:

We have a hypothetical 2D inviscid, steady, uniform and parallel, potential flow, described by
the velocity vector ## \vec{v} = <u,w>##, with ##u= U[z]## and ##w= W[z]##. It is moving parallel to a stationary plate that lies along the ##x## axis. By “parallel,” it is meant that flow is everywhere parallel to the plate.
By “uniform”, it is meant that the flow is spatially uniform. By “steady”, it is meant that the flow
is time invariant.

When solving for a velocity profile, my first thought was to consult the Navier-Stokes Equations for ractangular coordinates and go from there. What I was thinking was steady implies ##\partial_t = 0##, inviscid implies ##\mu = 0## (or would this be ##\nabla \times \vec{v} = 0##?). Parallel implies ##v_y = 0## where ##y## is orthogonal to the base plate (I think ##u## and ##w## move in the plate direction and from side-to-side respectively (any ideas here)? Potential implies the existence of some scalar ##\phi : \vec{v} = \nabla \phi##. Uniform implies ##\partial_x v = \partial_z v = 0##.

Can someone confirm this?

If I'm right, the equation of motion would simply be ##\nabla ^2 \vec{v} = 0 \implies \nabla^2 u = 0## and ##\nabla^2 w = 0##. Do you agree or disagree?
 
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Thanks for the post! Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
 

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