The Research On Theory And Method Of Wave-generating Technology

In the field of naval architecture and ocean engineering, numerical simulation and modeltest are two main approaches to investigate the wave-structure interaction problems. Wavegenerating is the key aspect of the numerical wave tank technique and also the correspondingphysical basin. Effective numerical wave generating method could improve the efficiency ofthe numerical wave tank, which in turn is beneficial for researching the wave generatingprocess in the real physical world as well. Wave-maker is one of the fundamental equipmentsfor ocean basin, and the system integration and control strategy are the indispensable basis forgenerating high quality waves. Besides wave generating, active absorbing the wave reflectedby the model and beach also matters a lot for both the numerical and physical tank. Otherwise,this part of the wave would again be pushed away by the wave-maker towards to the model,which is also referred as second reflection. Obviously, this additional reflection will inevitablycorrupt the accuracy of the test. This thesis concerns on the following issues: numerical wavegenerating; the system integration and motion control of multi-directional wave maker; activewave absorption. The detailed illustration is as follows:(1) Viscous numerical wave tank was established based on CFD theory, by which3Dsecond order stokes wave and solitary wave were simulated using velocity boundarytechnique and mass source techniques respectively. Highly non-linear boundaryelement method coupled with Mixed-Euler-Lagrange method were employed todevelop the numerical wave tank. Based on this model and using the phase focusingtheory, the focus wave phenomenon was simulated through flap-type wave maker.(2) Based on the analysis of the imported control server, the control system of themulti-directional wave maker was set up by Sercos bus. Moreover, the position controland interpolation programs were developed as well. Through all these fundamentalwork, the accurate motion control was realized. The Synchronous Control ofmulti-wave-maker was achieved by synchronal testing of the regular wave during thewave making process.(3) According to linear superposition theory, the advanced white noise irregular wavegenerating technique was investigated and conducted in the wave basin. The generation of oblique wave and short crest wave by unilateral rock-flap multi-directionalwave-maker were investigated and the physical test was also conducted in the wavebasin by differentiating control of wave-maker. Frequency and directional spectrumanalysis programs were developed. Through spectral analysis and iteration amendment,high quality oblique regular, oblique irregular and shor crest wave were obtained in thebasin.(4) Through potential and linear superposition theories, the principle of active waveabsorption was investigated. The two mainstream theoretical models were integrated ina single framework. The active wave absorption technique was re-interpreted throughthe angle of modern control theory. As a consequence, the intelligent control wasintroduced and a new control strategy was proposed as well.(5) The new active wave absorption theory was verified by both numerical and physicalsimulations. Specifically, in the numerical wave flume, the proposed method andprevious one were comparatively studied; For physical situation, the flap-typeprototype was established. According to the distinguished features of active waveabsorption wave-maker, the real time position compensation control system wasdeveloped and online modification of trace of the rocker was realized, and theperformance was assessed by the reflection separation algorithm.