.Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_dp_der2

Information

Function that implements the second order derivative of Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_dp, assuming a constant flow coefficient.

When called with dp_der=der(dp) and dp_der2=der(dp_der), this function returns the second order derivative of m_flow with respect to time. When called with dp_der=1 and dp_der2=0, this function returns the second order derivative of m_flow with respect to dp.

Interface

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;

Revisions

• January 4, 2019, by Michael Wetter:
  Set `Inline=false`.
  See #1070.
• May 1, 2017, by Filip Jorissen:
  Revised implementation such that Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_dp is C2 continuous. See #725.
• January 22, 2016, by Michael Wetter:
  Corrected type declaration of pressure difference. This is for #404.
• July 29, 2015, by Michael Wetter:
  First implementation to avoid in Dymola 2016 the warning "Differentiating ... under the assumption that it is continuous at switching".