[fluidmechanics]

Dear all;

I want to know in order to simulate pitch and plunge motion, do we have to divide numerical domain into two subdomains and rotate or translate the near walls subdomain and fix the outer one, or no, rigid motion of the entire domain will yield in true aerodynamic coefficients?

According to "SU2_AIAA_ASM 2013", page 27, "for pitching and plunging, rigid motion of the entire domain is true. Am I right or misunderstand?

Thanks a lot.

[economon]

Hi Mike,

There are multiple methods for computing unsteady flows on dynamic meshes, and depending on the particular problem, one choice may be more appropriate.

For instance, a pitching/plunging airfoil problem with a typical far-field boundary (not a solid outer boundary) could be simulated by pitching/plunging the entire mesh in a rigid fashion (i.e., no interior points move relative to each other). However, if the airfoil is pitching/plunging in a wind tunnel with fixed outer walls, the airfoil surface should be moved and then the interior mesh deformed around it while holding the outer walls fixed.

SU2 can handle both of these options, and this is an active area of development. The options for grid movement can be found within the unsteady flow section of the configuration file.

Hope this helps,
Tom

[Rachit]

Hi Thomas,

Can you please tell me if SU2 can facilitate translational rigid body motion? Or is it just rotational motion?

Regards,
Rachit

[economon]

Originally Posted by Rachit

Hi Thomas,

Can you please tell me if SU2 can facilitate translational rigid body motion? Or is it just rotational motion?

Regards,
Rachit

Hi Rachit,

As of v2.0.6, SU2 supports rigid motion transformations for translation, pitching, plunging, and rotation. The following options specify the parameters controlling each type of motion to be used with unsteady simulations (it is set to a pitching case here by default):

%
% Mesh motion for unsteady simulations (NO, YES)
GRID_MOVEMENT= YES
%
% Type of mesh motion (NONE, FLUTTER, RIGID_MOTION, FLUID_STRUCTURE)
GRID_MOVEMENT_KIND= RIGID_MOTION
%
% Coordinates of the rigid motion origin
MOTION_ORIGIN_X= 0.25
MOTION_ORIGIN_Y= 0.0
MOTION_ORIGIN_Z= 0.0
%
% Translational velocity (m/s) in the x, y, & z directions (RIGID_MOTION only)
TRANSLATION_RATE_X = 0.0
TRANSLATION_RATE_Y = 0.0
TRANSLATION_RATE_Z = 0.0
%
% Plunging angular freq. (rad/s) in x, y, & z directions (RIGID_MOTION only)
PLUNGING_OMEGA_X= 0.0
PLUNGING_OMEGA_Y= 0.0
PLUNGING_OMEGA_Z= 0.0
%
% Plunging amplitude (m) in x, y, & z directions (RIGID_MOTION only)
PLUNGING_AMPL_X= 0.0
PLUNGING_AMPL_Y= 0.0
PLUNGING_AMPL_Z= 0.0
%
% Angular velocity vector (rad/s) about x, y, & z axes (RIGID_MOTION only)
ROTATION_RATE_X = 0.0
ROTATION_RATE_Y = 0.0
ROTATION_RATE_Z = 0.0
%
% Pitching angular freq. (rad/s) about x, y, & z axes (RIGID_MOTION only)
PITCHING_OMEGA_X= 0.0
PITCHING_OMEGA_Y= 0.0
PITCHING_OMEGA_Z= 106.69842
%
% Pitching amplitude (degrees) about x, y, & z axes (RIGID_MOTION only)
PITCHING_AMPL_X= 0.0
PITCHING_AMPL_Y= 0.0
PITCHING_AMPL_Z= 1.01
%
% Pitching phase offset (degrees) about x, y, & z axes (RIGID_MOTION only)
PITCHING_PHASE_X= 0.0
PITCHING_PHASE_Y= 0.0
PITCHING_PHASE_Z= 0.0

Hope this helps,
Tom

[Rachit]

Dear Tom,

Thanks for the reply. Was wondering so as the translational velocity options are not mentioned on the website page of the configuration file.

Regards,
Rachit

[albinjohny]

Thankyou economon for the DYNAMIC MESH DEFINITION file u sent.