9.0
general documentation
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Examples of data settings for head losses

the cs_user_head_losses function is used to compute the values of the head loss term, and is called at each time step for each previously defined head loss volume zone.

(cs_user_zones.c and cs_user_head_losses.cpp)

Volume zones may be defined using the GUI, or through the cs_user_zones (in cs_user_zones.cpp).

cku is the local head loss term.

It appears on the momentum as follows:

\[ \rho \der{\vect{u}}{t} = - \grad p + \vect{headloss} \: (+\: \text{other terms})\]

with

\[ \vect{headloss} = - \rho \tens{cku}\cdot \vect{u} \,\: (\text{in } kg\cdot m^{-2} \cdot s^{-1})\]

For a distributed head loss, let ${ \tens{\xi_l} = \dfrac{\tens{dh_l}}{(0.5 \rho u^2)}}$ given by the litterature ( $ \tens{dh_l} $ is the head loss per unit length)

the source term tspdc is equal to $\tens{dh_l} = - \tens{\xi_l}(0.5\rho\vect{u}^2)$

we have $ \tens{cku} = 0.5\tens{\xi_l}|\vect{U}| $

For a singular head loss, let $\tens{\xi_l} = \dfrac{\tens{dh_s}}{0.5\rho\vect{u}^2}$ given by the litterature ( $\tens{dh_s} $ is the singular head loss)

the source term tspdc is equal to

\[\frac{\tens{dh_s}}{L} = - \frac{\tens{\xi_l}}{L} (0.5 \rho\vect{u}^2)\]

. We have

\[\tens{cku} = 0.5\frac{\tens{\xi_s}}{L}|\vect{u}|\]

where $ L $ is the length over which we have chosen to represent the singular head loss.

Head loss setting examples

Here is the list of examples: