Study On The Flow-induced Vibration Characteristics Of Gate Pier And Its Mitigation Measure

The feature of water conservancy hub is mass flow, high velocity. When the floodwater flows through the outlet structure, turbulent flow will cause the gate pier and lighthydraulic structure vibration, namely the flow-induced vibration. It’s frequentlyreported that there are many safety accidents caused by flow-induced vibration both athome and abroad. So we must pay full attention to the safty and stability of hydraulicstructure under the action of pulsating flow load. The water level difference betweenupstream and downstream is small, and the flow state is complex in differentoperation condition. The water-flow of low frequency and large range will cause thegate pier larger vibration, and even endanger its safety. So the dynamic response andstability problem is prominent. This paper makes research of flow-induced vibrationcombined with physical model test and prototype observation test and numericalsimulation of gate pier. It also probes into methods to reduce vibration and whatoperation should be avoided. The conclusion of this paper has important significancefor hydraulic design in the future. The main research results are as follows：(1) The hydrodynamic loads and the dynamic responses of the gate pier weretested in hydraulic model and hydro-elastic model. It makes study on the amplitudeand power spectrum characteristics of the gate pier’s hydrodynamic load and dynamicresponse. It provides basis for subsequent numerical simulation and judging whetherresonance occours.(2) Based on the finite element theory, the gate pier’s three-dimensional finiteelement model was established by the software-ANSYS, and its dry mode and wetmodal properties can be be calculated to analyze whether the gate pier would occurstochastic resonance with the flow. The gate pier’s dynamic response can becalculated by adding the hydrodynamic load tested by hydraulic model to numericalmodel, which was used to compare with the dynamic response tested by physicalmodel. And also, the gate pier’s safety and stability can be evaluated by comparing itsdynamic stress and displacement with relevant decision standard.(3) The gate pier’s vibration characteristic was further researched and itsvibration reason was revealed through prototype observation test. This paper alsopoints out the dangerous operation condition and it verified that combining withnumerical simulation and physical model test and prototype observation is the mosteffective way to solve fluid-solid interaction. (4) Combined with numerical simulation, this paper makes study of the gatepier’s vibration damping measure and it founded that the reinforcement at the locationof gate pier’s head and tail using box-girder is an effective method of vibrationreduction.