Dear OGS community,
I'm modeling dynamic subsurface pipe leakage using the RICHARDS equation
and I face a little problem.

I conduct the leakage (water flow through pipe defect) by assigning a
constant pressure head BC to the lower part of the pipe. After
computation, the nodal velocities directly on this boundary stay
constant throughout a scenario with a changing pressure gradient.

Can anyone tell me how (or refer to anyone who might know) OGS does the
calculation of nodal velocities on nodes of a constant pressure head
boundary? In my model, these velocities seem to be only gravity and not
pressure gradient driven.

OGS calculates the Darcy velocity of fluid at Gauss points of each element, and extrapolates the Gauss point velocity to nodes for output if keywords
VELOCITY_X1, VELOCITY_Y1, VELOCITY_Z1 are given in .out file.

···

On 03/04/2015 04:16 PM, Aaron Peche wrote:

Dear OGS community,
I'm modeling dynamic subsurface pipe leakage using the RICHARDS equation
and I face a little problem.

I conduct the leakage (water flow through pipe defect) by assigning a
constant pressure head BC to the lower part of the pipe. After
computation, the nodal velocities directly on this boundary stay
constant throughout a scenario with a changing pressure gradient.

Can anyone tell me how (or refer to anyone who might know) OGS does the
calculation of nodal velocities on nodes of a constant pressure head
boundary? In my model, these velocities seem to be only gravity and not
pressure gradient driven.

All right. The model works. There was a conceptual error.
Thank you Wenqing.

···

Am 3/9/2015 um 12:08 PM schrieb Wenqing Wang:

OGS calculates the Darcy velocity of fluid at Gauss points of each element, and extrapolates the Gauss point velocity to nodes for output if keywords
VELOCITY_X1, VELOCITY_Y1, VELOCITY_Z1 are given in .out file.

On 03/04/2015 04:16 PM, Aaron Peche wrote:

Dear OGS community,
I'm modeling dynamic subsurface pipe leakage using the RICHARDS equation
and I face a little problem.

I conduct the leakage (water flow through pipe defect) by assigning a
constant pressure head BC to the lower part of the pipe. After
computation, the nodal velocities directly on this boundary stay
constant throughout a scenario with a changing pressure gradient.

Can anyone tell me how (or refer to anyone who might know) OGS does the
calculation of nodal velocities on nodes of a constant pressure head
boundary? In my model, these velocities seem to be only gravity and not
pressure gradient driven.