Base class for all wave pressure solvers. Calculates wave pressure using Bernoulli equation.

Derived classes

• vtb::core::Wave_pressure_solver_opencl< T >
• vtb::core::Wave_pressure_solver_openmp< T >

Types

• using vec3 = Vector3< T >
• using array4 = Array< T, 4 >
• using array3 = Array< T, 3 >
• using array2 = Array< T, 2 >
• using grid4 = Grid< T, 4 >
• using grid3 = Grid< T, 3 >
• using panel_array = std::vector< panel_type >
• using panel_type = Ship_hull_panel< T, 3 >

Fields

• Grid< T, 3 > _velocity_potential_grid
• Array< T, 4 > _velocity_potential

  Past values of velocity potential.

Methods

• store_past_values(const Array< T, 3 > & phi, const Grid< T, 3 > & grid) -> voidprotected
• resistance() const -> bool
• resistance(bool rhs) -> void

  Take into acccount ship resistance to flow. Ship resistance to flow is calculated for each ship hull panel using the following formula. $$\vec{F}_\text{resistance} = \rho V \vec{v} \left| \vec{a} + \left(\vec{r}\times\vec\omega\right)\times\vec\omega + \vec{r}\times\vec\alpha \right| \vec{n}$$ Here $\rho$ is water density, $V$ is volume of the tetrahedron with panel as a base and centre of floatation as the origin, $\vec{v}$ is ship linear velocity, $\vec{a}$ is ship linear acceleration, $\vec\omega$ is ship angular velocity, $\vec\alpha$ is ship angular acceleration, $\vec{r}$ is a vector from ship centre of gravity to the centre of the panel, $\vec{n}$ is panel surface normal. Total force acting on the panel is calculated as $\vec{F}_\text{total} = \vec{F}_\text{resistance} + \vec{F}_\text{wave}$.

• clip() const -> bool

  Clamp grid to panels?

• clip(bool b) -> void
• solve(Array< T, 2 > wavy_surface, const Grid< T, 4 > & velocity_potential_grid, Array< T, 3 > velocity_potential, panel_array & panels, const Ship< T > & ship) -> voidvirtual

  Compute pressure force applied to the centre of each ship hull panel.

  wavy_surface

  two-dimensional $(x,y)$ surface elevation array

  
  

  velocity_potential_grid

  Four-dimensional $(t,z,x,y)$ grid for each point of which velocity potential is calculated.

  
  

  velocity_potential

  three-dimensional $(z,x,y)$ fluid velocity potential array

  
  

  panels

  Triangular panels comprising wetted part of the ship hull.

  
  

  ship

  The ship.

  
  

  • Compute pressure using Bernoulli equation: $$p(x,y,z,t) = -\rho \left( \phi_t + \frac{1}{2}\left( \phi_x^2 + \phi_y^2 + \phi_z^2 \right) + g z \right),$$ where $\rho$ — fluid density, $g$ — gravitational acceleration, $\phi$ — velocity potential.
  • Determne pressure force for each panel as $$\vec{F}_{wave} = \vec{x} \vec{n} S,$$ where $S$ — panel area, $\vec{x}$ — radius vector of the panel centre relative to the ship hull centre of mass, $\vec{n}$ — normal vector of the panel facing outside the hull. Multiplication is pointwise.

  Date

  2018-08-23

  Author

  Ivan Gankevich

• ~Wave_pressure_solver()virtual