# Annular pipe to circular pipe velcoity calculation

**82**

Hi everyone,

Does anyone know how to estimate velocity v2 in the circular pipe if given the velocity in an upstream annular pipe is v1? t is a very small gap compared to l1 and l2 so the flow travels in a different direction as shown in the diagram.

Initially, I was thinking of using mass conservation so the velocity only related to the cross-section area ratio. However, I am not sure how to account for the velocity loss in direction change and the vortices generated at the turning angle.

Another idea is to use the Bernoulli equation and accounts for the minor losses at the turn and at circular pipe 2. However, I only know P1 at the upstream but not sure about P2.

Any hints would be very much appreciated.

Best regards,

Lugia_06

## Answers

929Continuity equation

rho_1 * V_1 * A_1 = rho_2 * V_2 * A_2

8,851Remember that unless you have compressible flow there is no velocity (volume) loss in the system. With compressible flow, mass is conserved.