Inviscid flow
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In fluid dynamics there are problems that are easily solved by
using the simplifying assumption of an ideal fluid that has no
viscosity. The flow of a fluid that is assumed to have no viscosity
is called inviscid flow.[1]The flow of fluids with low values of
viscosity agree closely with inviscid flow everywhere except close
to the fluid boundary where the boundary layer plays a significant
role.[2]Contents
[hide]
1 Reynolds number 2 Problems with the inviscid-flow model 3
References
3.1 Notes 4 See also
[edit] Reynolds number
The assumption of inviscid flow is generally valid where viscous
forces are small in comparison to inertial forces. Such flow
situations can be identified as flows with a Reynolds number much
greater than one. The assumption that viscous forces are negligible
can be used to simplify the Navier-Stokes solution to the Euler
equations.
In the case of incompressible flow, the Euler equations
governing inviscid flow are:
which, in the steady-state case, can be solved using potential
flow theory. More generally, Bernoulli's principle can be used to
analyse certain time-dependent compressible and incompressible
flows.
[edit] Problems with the inviscid-flow model
While throughout much of a flow-field the effect of viscosity
may be very small, a number of factors make the assumption of
negligible viscosity invalid in many cases. Viscosity cannot be
neglected near fluid boundaries because of the presence of a
boundary layer which enhances the effect of even a small amount of
viscosity. Turbulence is also observed in some high-Reynolds-number
flows, and is a process through which energy is transferred to
increasingly small scales of motion until it is dissipated by
viscosity.
[edit] References
Clancy, L.J. (1975), Aerodynamics, Pitman Publishing Limited,
London. ISBN 0 273 01120 0 Kundu, P.K., Cohen, I.M., & Hu, H.H.
(2004), Fluid Mechanics, 3rd edition, Academic Press. ISBN
0121782530, 9780121782535
[edit] Notes
1. ^ Clancy, L.J., Aerodynamics, p.xviii
2. ^ Kundu, P.K., Cohen, I.M., & Hu, H.H., Fluid Mechanics,
Chapter 10, sub-chapter 1
[edit] See also
Viscosity Fluid Dynamics Stokes Flow, in which the viscous
forces are much greater than inertial forces.
Couette Flow
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