Function that implements the second order derivative of BuildingSystems.Fluid.BaseClasses.FlowModels.basicFlowFunction_dp with respect to the mass flow rate.
function basicFlowFunction_dp_der2 extends Modelica.Icons.Function; input Modelica.Units.SI.PressureDifference dp(displayUnit = "Pa") "Pressure difference between port_a and port_b (= port_a.p - port_b.p)"; input Real k(min = 0, unit = "") "Flow coefficient, k=m_flow/sqrt(dp), with unit=(kg.m)^(1/2)"; input Modelica.Units.SI.MassFlowRate m_flow_turbulent(min = 0) "Mass flow rate where transition to turbulent flow occurs"; input Real dp_der "1st derivative of pressure difference between port_a and port_b (= port_a.p - port_b.p)"; input Real dp_der2 "2nd derivative of pressure difference between port_a and port_b (= port_a.p - port_b.p)"; output Real m_flow_der2 "2nd derivative of mass flow rate in design flow direction"; end basicFlowFunction_dp_der2;