Describe the bug

I belive the code in ThrottlingValve adapts IEC / ANSI / ISA valve sizing for liquid service, but the Universal Gas Sizing for gas service, and this is a little confusing since the Cv in UGS is actually Cg , where Cg = Cv * Cl if I read the formulas right.

Further the sine factor used is for degrees, I suspect it should be radian i.e. Math.sin(59.64/Cl) (where Cl is assumed = 30). I am not 100% sure, since I dont code in java.
So, important information is that the Cv for gas valve is actually Cg, and Cv is Cg/30. Ideally both both liquid and gas would be on "Cv" basis. For gas could be fixed by coverting Cv to Cg when Cv is given as input and converting Cg to Cv when Cv is calculated.

For the sine function it appears in calcCv, calcPercentValveOpening, calcValvePout, calcmassflow

From: https://www.w3schools.com/java/ref_math_sin.asp
Definition and Usage
The sin() method returns the sine of an angle.

Note: Angles are measured in radians.

Tip: You can use the constant Math.PI to make fractions of PI for angles.

*/
public double calcCv(double Pus, double Pds, double rhous, double massFlowRate,
   double percentValveOpening) {
 // Sine of 3417 / 30.0
 double sineFactor = Math.sin(3417 / 30.0);

 // Calculate Cv
 double Cv = massFlowRate / (0.0457 * Math.sqrt(Pus * 100.0 * rhous) * sineFactor
     * Math.sqrt((Pus - Pds) / Pus) * percentValveOpening / 100.0);

 return Cv;
}