An experimental Study to Measure the Resonance Frequency of a Submerged Beam in Fluid

Various experimental techniques have been used to measure the rheological properties of fluids. One of the common techniques is to monitor the change in the dynamic response of a beam submerged in the fluid. Using this principle, the present study employed a cantilever beam to characterize the effect of fluid viscosities on the natural frequency of the beam. For this purpose, a simple and low cost electromagnetic setup was utilized to excite the cantilever beam. The frequency of electromagnetic setup was swept to allow the visualization of the beam resonance. Therefore, this approach was first applied to measure the dynamic response of the cantilever beam in air then, the response of the same beam was obtained while it was partially submerged in fluids, i.e., in water and different oils. The effect of beam parameters, e.g. the thickness, length and the submerged depth on the natural frequency of the beam were also studied. It was found that increasing the viscosity of the fluid lowers the natural frequency and the maximum amplitude of the cantilever beam. In addition, a further reduction in the resonance frequency of the beam was obtained by increasing the submerged depth.