- #1
ostritch
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I am making a basic structural engineering software program for modelling cylindrical pipes. I want to model the effect of fluid inside the pipes. For static fluid I let the user input the internal pressure and density of the fluid in each element. For moving fluid I additionally want to let them specify a velocity. This will let me calculate skin friction and centrifugal forces due to curved pipe sections.
The density and velocity are constant over pipeline. I know this is not very realistic due to losses and Bernoulli etc but it is satisfactory for my structural analysis purposes. I am now reading about dynamic pressure and how a moving fluid can exert an addition dynamic pressure given by
0.5 * ρ * V2
where ρ is the fluid density and V is the fluid velocity.
Is this pressure applicable in my case? If I add this dynamic pressure to the user-specified internal pressure, then this total pressure will be assumed to act in every direction. Each discreet element in my pipeline is open at the ends,as its joined to adjacent elements. Am I correct in thinking that the pressure can only act on the pipe walls? If the internal pressure is higher than the external pressure, the pipe will tend to bulge and including a poisson's effect, the element will tend to shorten. I'm not sure if it is correct to include the dynamic pressure with the user internal pressure in this calculation. My understanding is that the dynamic pressure acts only in the direction of the fluid velocity i.e. towards the end cap of the element. Since there isn't a physical end cap, does this mean that this dynamic pressure does not affect the element?
Thank you for your help, this has been bothering me for a while.
The density and velocity are constant over pipeline. I know this is not very realistic due to losses and Bernoulli etc but it is satisfactory for my structural analysis purposes. I am now reading about dynamic pressure and how a moving fluid can exert an addition dynamic pressure given by
0.5 * ρ * V2
where ρ is the fluid density and V is the fluid velocity.
Is this pressure applicable in my case? If I add this dynamic pressure to the user-specified internal pressure, then this total pressure will be assumed to act in every direction. Each discreet element in my pipeline is open at the ends,as its joined to adjacent elements. Am I correct in thinking that the pressure can only act on the pipe walls? If the internal pressure is higher than the external pressure, the pipe will tend to bulge and including a poisson's effect, the element will tend to shorten. I'm not sure if it is correct to include the dynamic pressure with the user internal pressure in this calculation. My understanding is that the dynamic pressure acts only in the direction of the fluid velocity i.e. towards the end cap of the element. Since there isn't a physical end cap, does this mean that this dynamic pressure does not affect the element?
Thank you for your help, this has been bothering me for a while.