ocmw.core.physics module

Functions for calculating physical quantities.

pressure2depth	Convert pressure measured in seawater to a depth in metres below surface.
g_wgs84	Calculate gravity based on latitude on the WGS84 spheroid.
circulation2D	Calculate the circulation around an element define by the nodes at locations ( x , y ).
kinetic_energy_density_2D	Calculate kinetic energy density at a mesh element centroid
potential_energy_density_2D	Calculate potential energy density at a mesh element centroid
frictionCoeff	Convert as C100 drag coefficient to a bed friction coefficient.
chezy	Calculate the Chezy friction coefficient from the C_100 drag coeficient.
manning	Calculate the Manning friction coefficient based on the C_100 drag coefficient and the water depth.
strickler	Calculate the Strickler friction coefficient based on the C_100 drag coefficient and the water depth.
nikuradse	Calculate the Nikuradse friction coefficient based on the C_100 drag coeffieient and the water depth.

Functions for calculating physical quantities.

ocmw.core.physics.pressure2depth(d0, lat, P)

Convert pressure measured in seawater to a depth in metres below surface.

ocmw.core.physics.g_wgs84(lat)

Calculate gravity based on latitude on the WGS84 spheroid.

Parameters:

lat (float) – Latitude in decimal degrees.

Returns:

g (float) – Gravitational acceleration at latitude in m/s^2.

ocmw.core.physics.circulation2D(x, y, vel_x, vel_y)

Calculate the circulation around an element define by the nodes at locations ( x , y ).

Parameters:

• x (list[ float ]) – x coordinates of element nodes [ m ].

• y (list[ float ]) – y coordinate of element nodes [ m ].

• vel_x (list[ float ]) – x component of velocity at element nodes [ m/s ].

• vel_y (list[ float ]) – y component of velocity at element nodes [ m/s ].

Returns:

circ (float) – fluid circulation around element.

ocmw.core.physics.kinetic_energy_density_2D(mesh, depth, velx, vely, rho)

Calculate kinetic energy density at a mesh element centroid

ocmw.core.physics.potential_energy_density_2D(mesh, elev, rho)

Calculate potential energy density at a mesh element centroid

ocmw.core.physics.frictionCoeff(C100)

Convert as C100 drag coefficient to a bed friction coefficient.

ocmw.core.physics.chezy(C100)

Calculate the Chezy friction coefficient from the C_100 drag coeficient.

Parameters:

C100 (float) – C_100 drag coefficient (based on the velocity 100cm above bed).

Returns:

Cz (float) – Chezy friction coefficient.

ocmw.core.physics.manning(C100, h)

Calculate the Manning friction coefficient based on the C_100 drag coefficient and the water depth.

Parameters:

• C100 (float) – Drag coeffieient at 100cm above the beed.

• h (float) – water depth [ m ].

Returns:

m (float) – Manning friction coefficient.

ocmw.core.physics.strickler(C100, h)

Calculate the Strickler friction coefficient based on the C_100 drag coefficient and the water depth.

Parameters:

• C100 (float) – Drag coeffieient at 100cm above the beed.

• h (float) – water depth [ m ].

Returns:

S (float) – Strickler friction coefficient.

ocmw.core.physics.nikuradse(C100, h)

Calculate the Nikuradse friction coefficient based on the C_100 drag coeffieient and the water depth.

Parameters:

• C100 (float) – Drag coeffieient at 100cm above the beed.

• h (float) – water depth [ m ].

Returns:

ks (float) – Nikuradse friction coefficient.