.ModelicaReference.'flow'

Information

Declare flow (through) variable, which have to sum up to zero in connections

Examples

connector Pin
  Modelica.SIunits.Voltage v;
  flow Modelica.SIunits.Current i;
end Pin;

model A
  Pin p;
end A;

model Composition
  A a;
  A b;
  A c;
equation
  connect(a.p, b.p);
  connect(a.p, c.p);
end Composition;

From the connect statements in model Composition, the following connect equations are derived:

a.p.v = b.p.v;
a.p.v = c.p.v;
a.p.i + b.p.i + c.p.i = 0;

Syntax

class_definition :
   [ encapsulated ]
   [ partial ]
   ( class | model | record | block | connector | type |
     package | function )
   IDENT class_specifier

class_specifier :
   string_comment composition end IDENT
   | "=" base_prefix name [ array_subscripts ] [ class_modification ] comment
   | "=" enumeration "(" ( [enum_list] | ":" ) ")" comment

base_prefix :
   type_prefix

composition  :
   element_list
   { public element_list |
     protected element_list |
     equation_clause |
     algorithm_clause
   }
   [ external [ language_specification ]
              [ external_function_call ] [ annotation ";" ]
              [ annotation  ";" ] ]

element_list :
   { element ";" | annotation  ";" }

element :
   import_clause |
   extends_clause |
   [ final ]
   [ inner | outer ]
   ( ( class_definition | component_clause) |
     replaceable ( class_definition | component_clause)
        [constraining_clause comment])

component_clause:
   type_prefix type_specifier [ array_subscripts ] component_list

type_prefix :
   [ flow | stream ]
   [ discrete | parameter | constant ] [ input | output ]

Description

The flow prefix is used in order to generate equations for through variables, which sum up to zero in connections, whereas variables without the flow prefix are identical in a connection.