## Isothermal Liquid Domain

The isothermal liquid domain declaration is shown below.

```domain isothermal_liquid % Isothermal Liquid Domain % Copyright 2019 The MathWorks, Inc. parameters rho_L_atm = { 998.21, 'kg/m^3' }; % Liquid density at atmospheric pressure (no entrained air) entrained_air_model = foundation.enum.entrained_air_model.const; % Entrained air model % 1 - const % 2 - linear bulk_modulus_model = foundation.enum.bulk_modulus_model.const; % Isothermal bulk modulus model % 1 - const % 2 - linear beta_gain = { 6, '1' }; % Isothermal bulk modulus vs. pressure increase gain beta_L_atm = { 2.1791e9, 'Pa' }; % Liquid isothermal bulk modulus at atmospheric pressure (no entrained air) nu_atm = { 1.0034e-6, 'm^2/s' }; % Kinematic viscosity at atmospheric pressure air_ratio = { 0 , '1' }; % Entrained air-to-liquid volumetric ratio at atmospheric pressure polytropic_index = { 1.0, '1' }; % Air polytropic index rho_g_atm = {1.225, 'kg/m^3' }; % Gas (air) density at atmospheric condition p_min = { 0.1, 'Pa' }; % Minimum valid pressure p_atm = { 0.101325, 'MPa' }; % Atmospheric pressure p_crit = { 3, 'MPa' }; % Pressure at which all entrained air is dissolved end variables p = { 0.1, 'MPa' }; % Pressure end variables(Balancing = true) mdot = { 0 , 'kg/s' }; % Mass flow rate end end ```

It contains the following variables and parameters:

• Across variable p (absolute pressure), in MPa

• Through variable mdot (mass flow rate), in kg/s

• Parameter rho_L_atm, defining the liquid density at atmospheric pressure, with zero entrained air

• Enumerated parameter entrained_air_model, defining the entrained air parametrization, with two values:

• 0 — Entrained air is constant

• 1 — Entrained air is a function of pressure

• Enumerated parameter bulk_modulus_model, defining the bulk modulus parametrization, with two values:

• 0 — Bulk modulus is constant

• 1 — Bulk modulus is a function of pressure

• Parameter beta_gain, defining the ratio of bulk modulus to pressure increase, for when the bulk modulus is a function of pressure

• Parameter beta_L_atm, defining the liquid isothermal bulk modulus at atmospheric pressure, with zero entrained air

• Parameter nu_atm, defining the kinematic viscosity at atmospheric pressure

• Parameter air_ratio, defining the entrained air-to-liquid volumetric ratio at atmospheric pressure

• Parameter polytropic_index, defining the air polytropic index

• Parameter rho_g_atm, defining the air density at atmospheric condition

• Parameter p_min, defining the minimum valid pressure

• Parameter p_atm, defining the atmospheric pressure

• Parameter p_crit, defining the pressure at which all entrained air is dissolved, for when the amount of entrained air is a function of pressure

To refer to this domain in your custom component declarations, use the following syntax:

`foundation.isothermal_liquid.isothermal_liquid `