The dependence of flow volume on the pressure difference between the ports of a U-tube was determined for both laminar and turbulent flows of a magnetic fluid.The results showed that the dependence was linear in the case of laminar flow but was non-linear in the case of turbulent flow.In addition,the inductance and the voltage difference across two coils around the arms of the U-tube were calculated.The voltage difference was proportional to the flow volume and inversely proportional to the square of the coil length.These theoretical and experimental results demonstrate that the design of magnetic-fluid-based flow sensors is feasible.