def METHOD_NAME(self):
    variables = {}
    for domain in self.options.whole_cell_domains:
        if domain != "separator":
            Domain = domain.capitalize()
            # Electrolyte pressure
            p_k = pybamm.Variable(
                f"{Domain} pressure [Pa]",
                domain=domain,
                auxiliary_domains={"secondary": "current collector"},
            )
            v_mass_k = -pybamm.grad(p_k)
            v_box_k = v_mass_k
            div_v_box_k = pybamm.div(v_box_k)
            variables.update(
                self._get_standard_convection_variables(
                    domain, v_box_k, div_v_box_k, p_k
                )
            )
    return variables