Solve Incompressible Flow Over Converging Duct Oscillating Velocity

[sykiat89]

given an incompressible steady flow over a converging duct, the outlet velocity can be found just by using mass continuity equation, v1A1=v2A2.

However given a time dependent inlet velocity ie. oscillating velocity, how do i get the outlet velocity? assume the flow is incompressible and inviscid. Tried looking for navier-stoke i had no clue what it does.

 

[boneh3ad]

Continuity still holds even if your inlet is time-dependent.

 

[sykiat89]

Continuity still holds even if your inlet is time-dependent.

so, the equation, a1v1=a2v2 is applicable unless it is compressible flow? the last i remembered it is only for steady flow, and non of the books has a worked example for time-dependent inlet flow.

 

[minger]

If the flow is incompressible then that implies instantaneous "information" propagation. That is, any changes at the inlet will be immediately felt at the outlet.

Basically if you draw a control volume everything, since there can be no accumulation inside the CV due to incompressibility, then any changes at the inlet are immediately felt at the outlet.

So, yes, you're simple continuity equation should hold.