高曲率船舷外傾之船型常因拍擊現象而造成船體受損，若欲改善船體結構，船殼表面的壓力分佈情形及流場的變化情形是改善的重要依據。但因船體線型較為複雜，故本研究將目標簡化至固定橫斜高之楔型體。在楔型體入水衝擊時，本研究使用壓力計量測楔型斷面的壓力分佈，利用加速度規觀察楔型體入水衝擊過程的運動表現，同時利用PIV分析楔型入水衝擊時的水下流場觀測，藉此可達到同步量測。
本研究發現楔型表面的壓力值與受楔型衝擊而反彈的加速度會隨著入水速度增加而增加、隨著楔型橫斜高(deadrise)增加而減小。對於寬度為0.066公尺的10度楔型而言，在本研究的任何入水速度中，楔型斜面上的最大壓力峰值皆是出現在中後半段。而在楔型運動表現上，楔型體入水衝擊即會量測到第一個加速度峰值，而被楔形體排開的液體會開始沿著楔型斜面產生噴流，之後在受到重力影響下產生一個回捲衝擊楔型側邊的浪，此時會量測到一個大小約為加速度峰值三分之一倍的加速度。另外在PIV流場分析結果顯示，楔型體入水衝擊後的水下流場向外放射，且在楔型肩部產生較大的速度。

High curve flare of the ship hull will be damaged due to slamming phenomenon. If we want to improve the hull structure, the hull surface pressure distribution and changes of flow field are important basis for improvement. But a ship’s hull form is too complicate, so we simplify the research objectives to a wedge with a deadrise. When the wedge slams into the water, a pressure sensor was used in measuring the pressure distribution of wedge-section, and the dynamic performance was observed with accelerometer. The flow field can be obtained simultaneously by using PIV during the wedge slamming into the water.
This study points out that the pressure of wedge surface and the acceleration when wedge impacting on water will increase as falling velocity increase, and decrease as the wedge deadrise increase. For a 10 degree wedge with 0.066 meters wide, in any falling height of this study, the maximum peak pressure appears on the second half of the wedge slope. And in wedge dynamic performance part, a first acceleration peak is measured when wedge impact on water, and then the extruded liquid produces spray flow along the incline of wedge. Due to the effect of the gravity, the liquid will rollback to the side of wedge and acceleration is measured about one-third times of the acceleration peak. The PIV analysis of flow shows that the flow field is moving outward radially after the wedge slamming into water. At that moment, the shoulder of wedge exists a larger velocity vector during the wedge continued to sink.

[1] Von Karman, Th. (1929) The impact on seaplane floats during landing. National advisory committee for aeronautics, Technical note No. 321.
[2] Wagner H. (1932) Über Stross-und Gleitvorgänge an der Oberfläche von Flüssigkeiten Z. Angew. Math. Mech., Vol. 12, pp. 193–215.
[3] Dobrovol’skaya Z.N (1969) On some problems of similarity flow of fluid with a free surface. J. Fluid Mech. 36, pp. 805–829.
[4] Cointe R. and Armand J.-L. (1987) Hydrodynamic impact analysis of a cylinder. J. Offshore Mech. Artic Eng., Vol.109, pp. 237–243.
[5] Cointe R. (1989) Two-dimensional water-solid impact. J. Offshore Mech. Arctic Eng. 111, pp. 109–114.
[6] Greenhow M. (1987) Wedge entry into initially calm water. Appl. Ocean Re, Vol. 9, pp. 214-223.
[7] Muzaferija S., Peric M., Sames P. and T. Schellin (1998) A two-fluid Navier–Stokes solver to simulate water entry, In: Proc. 22nd Symp. Naval Hydrodyn. Washington D.C.: National Academy Press, pp. 638-651.
[8] Campana E.F., Carcaterra A., Ciappi E. and Iafrati A. (1998) Parametric analysis of slamming forces: compressible and incompressible phases, In: H. Kim, S.H. Lee and S.J. Lee (eds.), Proc. 3rd Int. Conf. Hydrodyn. ICHD-98. Seoul, Korea, pp. 167–172.
[9] Zhao R.; Faltinsen O. (1993) Water entry of two-dimensional bodies, J. Fluid Mech., Vol.246, pp.593-612.
[10] Mei Xiaoming; Liu Yuming; Yue Dick K. P. (1999) On the water impact of general two-dimensional sections, Applied Ocean Research, Vol.21, pp.1-15.
[11] Wu, G. X.; Sun, H.; He, Y. S. (2004) Numerical simulation and experimental study of water entry of a wedge in free fall motion, Journal of Fluids and Structures, Vol.19, pp.277-289.
[12] 陳震、蕭熙 (2006) 平底結構砰擊壓力峰值分析，上海交通大學學報，第40卷第6期，頁983-987。
[13] 蔡佳育 (2009) 二維楔型拍擊水面之數值模擬研究，碩士論文，國立成功大學系統及船舶機電工程研究所。
[14] Chuang S. L. (1966) Slamming of rigid shaped bodies with various deadrise angles, David Taylor Model Basin Report Number 0532346 (USA).
[15] Campbell I. M. C. and Weynberg P. A. (1980) Measurement of parameters affecting slamming, Wolfson Unit for Marine Technology Report Number 440.
[16] Smith N. J., Stansby P. K. and Wright J. R. (1998) The slam force on a flat plate in free flight due to impact on a wavecrest, J. Fluid Struct., Vol. 12 , pp. 183-96.
[17] Judge C., Troesch A. and Perlin M. (2004) Initial water impact of a wedge at vertical and oblique angles, J. Eng. Math., Vol. 48, pp. 279-303.
[18] Yettou E. M., Desrochers A. and Champoux Y. (2006) Experimental study on thewater impact of a symmetrical wedge, Fluid Dynamics Research, Vol.38, pp.47-66.
[19] Yang, S. H., Lee, H. H., Park, T. H.; Lee, I. H. and Lee, Y. W. (2007) Experimental and Numerical Study on the Water Entry of Symmetric Wedges and a Stern Section of Modern Containership, 10th International Symposium on Practical Design of Ships and Other Floating Structures, Houston, USA.
[20] 王子銘 (2011) 楔型船體落下水面衝擊反應之研究，碩士論文，國立高雄海洋科技大學海洋工程科技研究所。