# Documentation du code de simulation numérique SUNFLUIDH

## Web LIMSI

sunfluidh:velocity_initialization_examples

## Examples of data set

The user finds here some examples illustrating different configurations related to the namelist "Velocity_Initialization".
The data initialized by default, and not explicitly required, are generally not present for a sake of clarity.

#### Uniform Velocity field

The velocity is oriented along the J-direction only.
Its value is $1.5$.
Other velocity components are null.
  &Velocity_Initialization  I_Velocity_Reference_Value          = 0.0  , J_Velocity_Reference_Value          = 1.5  , K_Velocity_Reference_Value          = 0.0 ,
Initial_Field_Option_For_Velocity_I = 0    , Initial_Field_Option_For_Velocity_J = 0    , Initial_Field_Option_For_Velocity_K = 0,
White_Noise_Magnitude_For_Velocity_I= 0.0  , White_Noise_Magnitude_For_Velocity_J= 0.0  , White_Noise_Magnitude_For_Velocity_K= 0.0 /


By considering the default values of the namelist, it could simply be write as :

  &Velocity_Initialization   J_Velocity_Reference_Value          = 1.5  /

#### Parabolic velocity profile

The velocity is oriented along the J-direction and its mean value over the cross section of the domain is $1.5$.
The profile depends on The I-direction.
Other velocity components are null.
  &Velocity_Initialization   J_Velocity_Reference_Value          = 1.5 , Initial_Field_Option_For_Velocity_J = 1 /

#### "Spreading" velocity field from an inlet

Relevant when just one inlet is present.
The normal inflow is oriented along the I-direction.
Other velocity components are null.
  &Velocity_Initialization  Initial_Field_Option_For_Velocity_I = 3 /

The inflow velocity profile is spread out over the domain in the I-direction. The mean value of the velocity component is not required (but this value can still be set just to keep it mind).

#### Parabolic Velocity field with superimposed white noise

The velocity is oriented along the J-direction only. Its mean value is $1.5$.
The parabolic profile depends on The I-direction.
  &Velocity_Initialization  I_Velocity_Reference_Value          = 0.0  , J_Velocity_Reference_Value          = 1.5  , K_Velocity_Reference_Value          = 0.0 ,
Initial_Field_Option_For_Velocity_I = 0    , Initial_Field_Option_For_Velocity_J = 1    , Initial_Field_Option_For_Velocity_K = 0,
White_Noise_Magnitude_For_Velocity_I= 0.05  , White_Noise_Magnitude_For_Velocity_J= 0.1  , White_Noise_Magnitude_For_Velocity_K= 0.02 /


A white noise is superimposed on each velocity component such as :

• The random fluctuations on the I-velocity component are 5% of the mean value of the J-velocity component (because the mean value of the I-velocity component is null)
• The random fluctuations on the J-velocity component are 10% of the local value given by the parabolic profile.
• The random fluctuations on the K-velocity component are 2% of the mean value of the J-velocity (because the mean value of the K-velocity component is null)
Keep in mind the magnitude of fluctuations is defined in respect with the local value of the velocity component invoked only if it is a non-zero value . Otherwise this magnitude is relied on the maximum value given by I_Velocity_Reference_Value, J_Velocity_Reference_Value or K_Velocity_Reference_Value
sunfluidh/velocity_initialization_examples.txt · Dernière modification: 2017/09/25 17:06 de yann