Calculation of $u^\star$ , $ k $ and $\varepsilon$ from a diameter $ D_H $ and the reference velocity $U_{ref}$ for a circular duct flow with smooth wall (use for inlet boundary conditions). More...

Collaboration diagram for turbulence_bc_ke_hyd_diam:

Public Member Functions
subroutine	turbulence_bc_ke_hyd_diam (uref2, dh, rho, mu, ustar2, k, eps)

Detailed Description

Calculation of $u^\star$ , $ k $ and $\varepsilon$ from a diameter $ D_H $ and the reference velocity $U_{ref}$ for a circular duct flow with smooth wall (use for inlet boundary conditions).

Both $u^\star$ and $(k,\varepsilon )$ are returned, so that the user may compute other values of $ k $ and $\varepsilon$ with $u^\star$ .

We use the laws from Idel'Cik, i.e. the head loss coefficient $\lambda$ is defined by:

$|\dfrac{\Delta P}{\Delta x}| = \dfrac{\lambda}{D_H} \frac{1}{2} \rho U_{ref}^2$

then the relation reads $u^\star = U_{ref} \sqrt{\dfrac{\lambda}{8}}$ . $\lambda$ depends on the hydraulic Reynolds number $Re = \dfrac{U_{ref} D_H}{ \nu}$ and is given by:

for
$\lambda = \dfrac{64}{Re}$
for
$\lambda = \dfrac{1}{( 1.8 \log_{10}(Re)-1.64 )^2}$
for , we complete by a straight line
$\lambda = 0.021377 + 5.3115. 10^{-6} Re$

From $u^\star$ , we can estimate $ k $ and $\varepsilon$ from the well known formulae of developped turbulence

$k = \dfrac{u^{\star 2}}{\sqrt{C_\mu}}$

$\varepsilon = \dfrac{ u^{\star 3}}{(\kappa D_H /10)}$

Parameters

[in]	uref2	square of the reference flow velocity
[in]	dh	hydraulic diameter
[in]	rho	mass density $\rho$
[in]	mu	dynamic viscosity $\nu$
[out]	ustar2	square of friction speed
[out]	k	calculated turbulent intensity
[out]	eps	calculated turbulent dissipation $\varepsilon$

Constructor & Destructor Documentation

◆ turbulence_bc_ke_hyd_diam()

subroutine turbulence_bc_ke_hyd_diam	(	real(c_double), value	uref2,
		real(c_double), value	dh,
		real(c_double), value	rho,
		real(c_double), value	mu,
		real(c_double)	ustar2,
		real(c_double)	k,
		real(c_double)	eps
	)

The documentation for this interface was generated from the following file:

src/base/cs_c_bindings.f90

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ turbulence_bc_ke_hyd_diam()