## Isothermal Liquid Domain

The isothermal liquid domain declaration is shown below.

```domain isothermal_liquid % Isothermal Liquid Domain % Copyright 2019-2022 The MathWorks, Inc. parameters bulk_modulus_model = foundation.enum.bulk_modulus_model.const; % Isothermal bulk modulus model % 1 - const % 2 - linear air_dissolution_model = false; % Model air dissolution rho_L_atm = {998.21, 'kg/m^3'}; % Liquid density at atmospheric pressure (no entrained air) beta_L_atm = {2.1791e9, 'Pa' }; % Liquid isothermal bulk modulus at atmospheric pressure (no entrained air) beta_gain = {6, '1' }; % Isothermal bulk modulus vs. pressure increase gain nu_atm = {1.0034e-6, 'm^2/s' }; % Kinematic viscosity at atmospheric pressure air_fraction = {0.005, '1' }; % Volumetric fraction of entrained air in mixture at atmospheric pressure rho_g_atm = {1.225, 'kg/m^3'}; % Gas (air) density at atmospheric condition polytropic_index = {1.0, '1' }; % Air polytropic index p_atm = {0.101325, 'MPa' }; % Atmospheric pressure p_crit = {3, 'MPa' }; % Pressure at which all entrained air is dissolved p_min = {1, 'Pa' }; % Minimum valid pressure properties_range_check = simscape.enum.assert.action.error; % Pressure below minimum valid value % 0 - none % 1 - warn % 2 - error 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

• 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

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

• 0 — Entrained air is constant

• 1 — Entrained air is a function of pressure

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

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

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

• Parameter nu_atm, defining the kinematic viscosity at atmospheric pressure

• Parameter air_fraction, defining the volumetric fraction of air that is entrained at atmospheric pressure

• Parameter rho_g_atm, defining the air density at atmospheric condition

• Parameter polytropic_index, defining the air polytropic index

• 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

• Parameter p_min, defining the minimum valid pressure

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

`foundation.isothermal_liquid.isothermal_liquid `