Fluid flow through positive pressure gradient

[jacksimpson]

I am a student of 11th standard and being introduced to Bernoulli's principle made me wonder , how does flow takes place in positive pressure gradient (i.e. from low pressure region to high pressure region), in a diffuser or a diverging part of a venturi meter , since we know that flow always takes place from high pressure region to low pressure region ?.
it will be very kind of you to clear my confusion.
Thank you.

 

[Baluncore]

The fluid having kinetic energy will decelerate as it climbs the pressure gradient.

 

[boneh3ad]

Fluid motion does not always take place in the direction of negative pressure gradient; it always accelerates in that direction. If it already has motion against the pressure gradient, the gradient will serve to retard that motion, this the reason the velocity reduces through a diffuser.

 

[jacksimpson]

yes sir i understand that. But can I say that the fluid at the diffuser inlet has enough momentum to overcome the positive pressure gradient and hence the flow. and as the flow occurs the kinetic energy is converted into pressure energy

 

[boneh3ad]

Yes. That is essentially what Bernoulli's equation is telling you. It's an energy balance.

 

[sidali]

Maybe help : Industrial Flow Measurement
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