DynamicCoupled

class sharpy.solvers.dynamiccoupled.DynamicCoupled

The DynamicCoupled solver couples the aerodynamic and structural solvers of choice to march forward in time the aeroelastic system’s solution.

Using the DynamicCoupled solver requires that an instance of the StaticCoupled solver is called in the SHARPy solution flow when defining the problem case.

The settings that this solver accepts are given by a dictionary, with the following key-value pairs:

Name	Type	Description	Default
print_info	bool	Write status to screen	True
structural_solver	str	Structural solver to use in the coupled simulation	None
structural_solver_settings	dict	Dictionary of settings for the structural solver	None
aero_solver	str	Aerodynamic solver to use in the coupled simulation	None
aero_solver_settings	dict	Dictionary of settings for the aerodynamic solver	None
n_time_steps	int	Number of time steps for the simulation	None
dt	float	Time step	None
fsi_substeps	int	Max iterations in the FSI loop	70
fsi_tolerance	float	Convergence threshold for the FSI loop	1e-05
structural_substeps	int	Number of extra structural time steps per aero time step. 0 is a fully coupled simulation.	0
relaxation_factor	float	Relaxation parameter in the FSI iteration. 0 is no relaxation and -> 1 is very relaxed	0.2
final_relaxation_factor	float	Relaxation factor reached in relaxation_steps with dynamic_relaxation on	0.0
minimum_steps	int	Number of minimum FSI iterations before convergence	3
relaxation_steps	int	Length of the relaxation factor ramp between relaxation_factor and final_relaxation_factor with dynamic_relaxation on	100
dynamic_relaxation	bool	Controls if relaxation factor is modified during the FSI iteration process	False
postprocessors	list(str)	List of the postprocessors to run at the end of every time step	[]
postprocessors_settings	dict	Dictionary with the applicable settings for every psotprocessor. Every postprocessor needs its entry, even if empty	{}
controller_id	dict	Dictionary of id of every controller (key) and its type (value)	{}
controller_settings	dict	Dictionary with settings (value) of every controller id (key)	{}
cleanup_previous_solution	bool	Controls if previous timestep_info arrays are reset before running the solver	False
include_unsteady_force_contribution	bool	If on, added mass contribution is added to the forces. This depends on the time derivative of the bound circulation. Check filter_gamma_dot in the aero solver	False
steps_without_unsteady_force	int	Number of initial timesteps that don’t include unsteady forces contributions. This avoids oscillations due to no perfectly trimmed initial conditions	0
pseudosteps_ramp_unsteady_force	int	Length of the ramp with which unsteady force contribution is introduced every time step during the FSI iteration process	0

convergence(k, tstep, previous_tstep)

Check convergence in the FSI loop.

Convergence is determined as:

\[\epsilon_q^k = \frac{|| q^k - q^{k - 1} ||}{q^0}\]

\[\epsilon_\dot{q}^k = \frac{|| \dot{q}^k - \dot{q}^{k - 1} ||}{\dot{q}^0}\]

FSI converged if \(\epsilon_q^k < \mathrm{FSI\ tolerance}\) and \(\epsilon_\dot{q}^k < \mathrm{FSI\ tolerance}\)

get_g()

Getter for g, the gravity value

get_rho()

Getter for rho, the density value

initialise(data, custom_settings=None)

Controls the initialisation process of the solver, including processing the settings and initialising the aero and structural solvers, postprocessors and controllers.

static interpolate_timesteps(step0, step1, out_step, coeff)

Performs a linear interpolation between step0 and step1 based on coeff in [0, 1]. 0 means info in out_step == step0 and 1 out_step == step1.

Quantities interpolated: * steady_applied_forces * unsteady_applied_forces * velocity input in Lagrange constraints

process_controller_output(controlled_state)

This function modified the solver properties and parameters as requested from the controller.

This keeps the main loop much cleaner, while allowing for flexibility

Please, if you add options in here, always code the possibility of that specific option not being there without the code complaining to the user.

If it possible, use the same Key for the new setting as for the setting in the solver. For example, if you want to modify the structural_substeps variable in settings, use that Key in the info dictionary.

As a convention: a value of None returns the value to the initial one specified in settings, while the key not being in the dict is ignored, so if any change was made before, it will stay there.

run()

Run the time stepping procedure with controllers and postprocessors included.

set_g(new_g)

Setter for g, the gravity value

set_rho(new_rho)

Setter for rho, the density value