GLL implies Gauss Lobatto Legendre which is the Gauss quadrature for a constant weight function with both points endpoints included. implies Gauss Radau Jacobi quadrature with weights and the endpoint x=-1 included.
Volumetric flow rate per unit width W as a function of Reynolds number for closed-position piston-wall gap of g=0.025 L. The value for for both air and water are used. The mass flow rate is