Download NS3D v2.14: user's manual

20
Chapter 2
Compilation and execution
*** Type of simulation ***
perturbative_________________ T
linear___________________ T
*** Base state (only perturbative run) ***
base2D_type__________________ tanh
*** Initial velocity ***
velo_type____________________ null
white_noise__________________ 1E-10
*** Output ***
output1_period_______________ 400
output2_period_______________ 1000
output3_period_______________ 0
ˆ lx, ly and lz are the dimensions Lx , Ly and Lz of the computational
domain along each physical direction.
ˆ dt is the fixed time step δt used by the time scheme.
ˆ begin is the arbitrary numerical value of initial time t0 of the simulation.
ˆ itmax is the number of time steps. Consequently, the initial time is begin
and the ending time is begin+itmax×dt.
ˆ de aliasing indicates whether dealiasing (see § 1.2.4) is applied (T) or
not (F). If dealiasing is applied, it is possible to choose between a squared
(1) or elliptic (2) dealiasing. radius truncation x, y, z, are the dealiasing radius rxk , ryk and rzk along each spectral direction.
ˆ viscosity is the viscosity ν of the fluid.
ˆ stratified indicates whether the simulation is in a stratified fluid (T)
or in a homogeneous fluid (F). In a stratified fluid, the Brunt–Väisälä
frequency N and the Schmidt number Sc must be defined.
ˆ 2omega is 2Ωb , twice the angular velocity of the rotating frame. The
non-rotating case corresponds to a value Ωb = 0.
ˆ perturbative indicates whether the simulation is non-perturbative (F)
or perturbative (T). In perturbative mode, the simulation can be linear
perturbative (linear=T) or nonlinear perturbative (linear=F). See § 1.1
for the meaning of the different options.
ˆ base2D type is only used for perturbative simulations. It defines the
two-dimensional base flow: