Continuous fibers are drawn by extruding molten polymer through spinneret nozzles. The fibers are formed by the balance of the tension from a winder and by the force of gravity. Fiber attenuation and interaction with the quenching air flow characterize this process. Calculations in FLUENT provide important local information about the fiber. For example, velocity, temperature and composition (e.g., solvent content in dry spinning) vary along the length of the fiber and these variations are in part due to interaction with the quenching air. The presence of fibers changes the flow, temperature and composition of the surrounding fluid. Thus, two-way coupling exists between the fibers and the quenching fluid. FLUENT analyzes system-level effects in fiber production processes, while simultaneously providing local information about the fiber velocity, temperature, fiber diameter and the solvent mass fraction.