Quasistatic model for two-strand yarn spinning

A theoretical model underlying a two-strand spinning system is given. Based on the force balance and dynamics characters of the system (mass conservation, energy conservation, and momentum conservation), this system of the equations governing the quasistatic two-strand yarn spinning is self-contained, so that the convergence point can be determined with ease for different inlet velocities, densities, sizes (diameters) of the two strands.