Experimental Investigation Of Sloshing Mechanism And Load Characteristics

The research of sloshing problem for ocean engineering and aerospace engineering focuses on three aspects:sloshing model experimental investigation, sloshing impact, sloshing-induced global force. In this paper, a systematic review of three issues was carried out firstly. Then, relevant experiments were respectively conducted to study similarity relationship on the free-surface due to the liquid sloshing, local impact under shallow-water conditions and sloshing-induced force with a large forcing amplitude. The main work and the conresponding conclusions were summarized as follows.(1) Study on similarity relationship on the free-surface due to the liquid sloshingBased on Froude scaling law, three two-dimensional GTT tanks were designed to analyze model test results for h/H= 0.2 under single impact sway. The bimodal characteristic of wave elevation during the process of liquid impacting tank wall was discussed and distinguish of bimodal characteristic on different scale tanks was explained. Moreover, through the analysis of sloshing flow in different dimension tanks, it was concluded that the similarity relationship of free-surface wave elevation was relative to the scale size. The Froude scaling law was approximately applicable for relatively large scale tank, while the result of the wave height in small scale moel tank test expanded to full scale was small due to the viscous effects. At last, the relationship between wave rise time/decay time and Froude scaling law was studied. The above research results provide a useful reference to model test design.(2) Experimental investigation of the sloshing impact with shallow-water conditionsSloshing impact tests for h/H= 0.125 were carried out to study the mechanism of liquid sloshing impact and the distribution of impact load under sway harmonic excitation. The lowest three natural frequency derived from theory was applied in the experiment. Wave amplitude together with high speed video were recorded to analyze the behavior of free surface; In addition, the distribution of impact pressure with different excitation frequency was studied and it was concluded that the most intense sloshing occurs in the vicinity of the first natural frequency. The number of sloshing impact dramatically reduced when non-dimensional forced frequency ratio ?/?1* was exceed 1.41. The spatial distribution of sloshing impact loads on side wall was also investigated. The results show the maximum impact pressure occurs near the free surface. Moreover, the locations impacted by liquid on side wall would raise with increasing excitation frequency and were sensitive to frequency.(3) Investigation of sloshing-induced force with a large forcing amplitudeExperimental investigations of different filling level were studied for sloshing problem of aircraft fuel tanks under different excitation frequency and amplitude. Sloshing phenomenon in ellipsoid tank was analyzed based on high speed video. By comparing experimental datum to numerical simulation and equivalent mechanical model, the limitation of numerical simulation and equivalent mechanical model was discussed. Moreover, the distribution of sloshing-induced force together with sloshing phenomenon was investigated. The work could provide a good reference for optimizing equivalent mechanical model and experimental design.