the operating mode model of the 2d stream to express the relation between mass rate, specific volume, area, and velocity
(Forall (?Self ?Time) (=> (Active ?Time 2d-Stream-Mass-Flow-Rate ?Self) (= (* (Lambda (?T) (If (= ?T ?Time) (Value-At (Mass-Rate (2d-Stream-Involved ?Self)) ?T))) (Lambda (?T) (If (= ?T ?Time) (Value-At (Specific-Volume (2d-Stream-Involved ?Self)) ?T)))) (* (Lambda (?T) (If (= ?T ?Time) (Value-At (Stream-Area (2d-Stream-Involved ?Self)) ?T))) (Lambda (?T) (If (= ?T ?Time) (Value-At (Velocity (2d-Stream-Involved ?Self)) ?T))))))) (Forall (?Self ?Time) (<=> (Active ?Time 2d-Stream-Mass-Flow-Rate ?Self) (And (2d-Stream-Mass-Flow-Rate ?Self) (Active ?Time 2d-Stream-Operating-Mode ?Self))))
(Forall (?Self ?Time) (=> (Active ?Time 2d-Stream-Mass-Flow-Rate ?Self) (= (* (Lambda (?T) (If (= ?T ?Time) (Value-At (Mass-Rate (2d-Stream-Involved ?Self)) ?T))) (Lambda (?T) (If (= ?T ?Time) (Value-At (Specific-Volume (2d-Stream-Involved ?Self)) ?T)))) (* (Lambda (?T) (If (= ?T ?Time) (Value-At (Stream-Area (2d-Stream-Involved ?Self)) ?T))) (Lambda (?T) (If (= ?T ?Time) (Value-At (Velocity (2d-Stream-Involved ?Self)) ?T))))))) (Forall (?Self ?Time) (<=> (Active ?Time 2d-Stream-Mass-Flow-Rate ?Self) (And (2d-Stream-Mass-Flow-Rate ?Self) (Active ?Time 2d-Stream-Operating-Mode ?Self))))