# Changeset 75 for palm/trunk/DOC/app/chapter_4.1.html

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Timestamp:
Mar 22, 2007 9:54:05 AM (15 years ago)
Message:

preliminary update for changes concerning non-cyclic boundary conditions

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• ## palm/trunk/DOC/app/chapter_4.1.html

 r72 bc_lr may also be assigned the values 'dirichlet/neumann' (inflow from left, outflow to the right) or 'neumann/dirichlet' assigned the values 'dirichlet/radiation' (inflow from left, outflow to the right) or 'radiation/dirichlet' (inflow from right, outflow to the left). This requires the multi-grid method to be used for solving the Poisson equation for perturbation pressure (see psolver) and it also requires cyclic boundary conditions along y (see
bc_ns).

and it also requires cyclic boundary conditions along y (see bc_ns).

In case of these non-cyclic lateral boundaries, a Dirichlet condition is used at the inflow for all quantities (initial vertical profiles - see initializing_actions - are fixed during the run) except u, to which a Neumann (zero gradient) condition is applied. At the outflow, a Neumann (zero gradient) condition is used for all quantities except v, which is set to its horizontal average along the outflow (e.g. v(k,:,nx+1) = average_along_y( v(k,:,nx)), and except w, which is set to zero (Dirichlet condition). These conditions ensure the velocity field to be free of divergence at the inflow and at the outflow. For perturbation gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero gradient) condition is used for the scalars. For perturbation pressure Neumann (zero gradient) conditions are assumed both at the inflow and at the outflow.

bc_ns may also be assigned the values 'dirichlet/neumann' (inflow from rear ("north"), outflow to the front ("south")) or 'neumann/dirichlet' assigned the values 'dirichlet/radiation' (inflow from rear ("north"), outflow to the front ("south")) or 'radiation/dirichlet' (inflow from front ("south"), outflow to the rear ("north")). This requires the multi-grid In case of these non-cyclic lateral boundaries, a Dirichlet condition is used at the inflow for all quantities (initial vertical profiles - see initializing_actions - are fixed during the run) except v, to which a Neumann (zero gradient) condition is applied. At the outflow, a Neumann (zero gradient) condition is used for all quantities except u, which is set to its horizontal average along the outflow (e.g. u(k,ny+1,:) = average_along_x( u(k,ny,:)), and except w, which is set to zero (Dirichlet condition). These conditions ensure the velocity field to be free of divergence at the inflow and at the outflow. For perturbation see initializing_actions - are fixed during the run) except u, to which a Neumann (zero gradient) condition is applied. At the outflow, a radiation condition is used for all velocity components, while a Neumann (zero gradient) condition is used for the scalars. For perturbation pressure Neumann (zero gradient) conditions are assumed both at the inflow and at the outflow.

cloud_physics =
.TRUE. requires moisture requires humidity = .TRUE. .
Detailed information about the condensation scheme is given in the the so-called Blackadar mixing length is used (l = kappa * z / ( 1 + kappa * z / lambda ) with the limiting value lambda = 2.7E-4 * u_g / f).

Important: The  upstream-spline scheme is not implemented for humidity and passive scalars (see moisture scalars (see humidity and passive_scalar) and requires the use of a 2d-domain-decomposition. The last conditions With passive_scalar switched on, the simultaneous use of humidity (see moisture) on, the simultaneous use of humidity (see humidity) is impossible.

_level

moisture

humidity

L .F.

phi

R R (10)

10 *  0.0

Height level from which on the moisture gradient defined by q_vertical_gradient which on the humidity gradient defined by q_vertical_gradient is effective (in m).

The height levels are to be assigned in ascending order. The

Important: The  upstream-spline scheme is not implemented for humidity and passive scalars (see moisture scalars (see humidity and passive_scalar) and requires the use of a 2d-domain-decomposition. The last conditions  alpha_surface = 0.0, bc_lr = bc_ns = 'cyclic'galilei_transformation = .F.cloud_physics  = .F.cloud_droplets = .F.,  moisture = .F., and prandtl_layer = .T..
= .F.cloud_physics  = .F.cloud_droplets = .F.,  humidity = .F., and prandtl_layer = .T..

Note that an inclined model domain requires the use of topography = 'flat' and a

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