This function calculates the Sherwood number for a flat gap according to Stephan [1].
[1]: Stephan, K.: Waermeuebergang und Druckabfall bei nicht ausgebildeter Laminarstroemung in Rohren und ebenen Spalten. Chemie-Ing.-Techn. Vol. 31, no. 12, 1959 pp. 773-778
function SherwoodNumberStephan input Modelica.Units.SI.Length dimension "characteristic dimension"; input Modelica.Units.SI.Length length "length of flat gap"; input Real Sc "Schmidt number"; input Real Re "Reynolds number"; output Real Sh "Sherwood number"; end SherwoodNumberStephan;