EHD Lubrication

Dowson-Hamrock Film Thickness

All of the below functions can be found in the dowson_hamrock module of the package.

This module contains functions related to Dowson-Hamrock film thickness calculations.

dowhamline(vel_entrain, force, alpha_p, e_eff, r_eff, eta, l_eff)

Calculate the mean film thickness in a line contact according to Dowson-Hamrock.

Parameters:

• vel_entrain (ndarray, scalar) – The entrainment velocity of the contact problem.
• force (ndarray, scalar) – The normal force in the contact.
• alpha_p (ndarray, scalar) – The pressure-viscosity coefficient of the lubricant.
• e_eff (ndarray, scalar) – The effective modulus of the contact problem.
• r_eff (ndarray, scalar) – The effective radius of the contact problem.
• eta (ndarray, scalar) – The dynamic viscosity of the lubricant.
• l_eff (ndarray, scalar) – The effective length of the contact.

Returns:

h_0 – The central lubricating film thickness in the contact.

Return type:

ndarray, scalar

dowhampoint(vel_entrain, force, alpha_p, e_eff, r_eff, eta)

Calculate the mean film thickness in a point contact according to Dowson-Hamrock.

Parameters:

• vel_entrain (ndarray, scalar) – The entrainment velocity of the contact problem.
• force (ndarray, scalar) – The normal force in the contact.
• alpha_p (ndarray, scalar) – The pressure-viscosity coefficient of the lubricant.
• e_eff (ndarray, scalar) – The effective modulus of the contact problem.
• r_eff (ndarray, scalar) – The effective radius of the contact problem.
• eta (ndarray, scalar) – The dynamic viscosity of the lubricant.

Returns:

h_0 – The central lubricating film thickness in the contact.

Return type:

ndarray, scalar

edowham(alpha_p, e_eff)

Calculate the elasticity parameter of the contact problem according to Dowson-Hamrock.

Parameters:

• alpha_p (ndarray, scalar) – The pressure-viscosity coefficient of the lubricant.
• e_eff (ndarray, scalar) – The effective modulus of the contact problem.

Returns:

param_elasticity – The elasticity parameter of the contact problem.

Return type:

ndarray, scalar

vdowham(eta, vel_entrain, e_eff, r_eff)

Calculate the velocity parameter of the contact problem according to Dowson-Hamrock.

Parameters:

• eta (ndarray, scalar) – The dynamic viscosity of the lubricant.
• vel_entrain (ndarray, scalar) – The entrainment velocity of the contact problem.
• e_eff (ndarray, scalar) – The effective modulus of the contact problem.
• r_eff (ndarray, scalar) – The effective radius of the contact problem.

Returns:

param_velocity – The velocity parameter of the contact problem.

Return type:

ndarray, scalar