All,

I am trying to use abaqus/cfd to solve bernoulli equation.

bernoulli eq: p1 + g * density * h1 +1/2 * density * v1^2 = p2 + g * density * h2 +1/2 * density * v2^2     (1)

continuity eq: v1 * A1 = v2 * A2 ... since A1 = A2, then v1 = v2             (2)

(2) into (1):  p1 + g * density * h1 = p2 + g * density * h2

solving for p2:   p2 = p1 + g * density * (h1 - h2)       (3)

the following values are assumed:

p1 = 2 atm = 202600 N/m^2; g = 9.81 m/s^2;  density = 1000 kg/m^3; h1 = 5m;   h2 = 10m;  v1 = v2 = 2 m/s;  pipe diameter = 0.1m

plug in the values, we will end up with:

p2 = 202600 + 9.81 * 1000 * (5 - 10) = 153500 Pa (N/m^2)

If my math is correct, this should be the approximately the pressure abaqus/cfd should show. Correct?

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however, this is not the case. abaqus/cfd is estimating p2 = 192200 Pa.. This value is 25% greater than the theoretical value. I was expecting that cfd would show a p2 less than calculated value simply because some lost due to friction (fitting and pipe length) are expected. 

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I have attached the INP, abaqus pressure output and also an schematic of the problem solved analytically.

so my question to the community is... What am I doing wrong???

it seems to me that some how, abaqus is not considering the gravity acceleration. I have changed to the g value to 981 (g x 100) and I am still getting the same 1.9e5 Pa. Why??? am I missing something?

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thanks for your time and hoping for some guidance :)

Marcelo