ESTIMATION OF WATER ENTRY FORCES, SPRAY PARAMETERS AND SECONDARY IMPACT OF FIXED WIDTH WEDGES AT EXTREME ANGLES USING FINITE ELEMENT BASED FINITE VOLUME AND VOLUME OF FLUID METHODS

In this paper, water entry of wedges with deadrise angles ranging from 10 to 80 degrees at two different velocities is simulated. Impact forces, spray parameters, cavity formation above the chine, and secondary impact forces due to the cavity formation are investigated with particular focus on the extreme angles. To this end, a two dimensional two-phase Finite-Element based Finite-Volume (FEM-FVM) code is developed and validated against experimental data with good compliance. Free surface modeling in this software is accomplished by applying Volume of Fluid (VOF) method. In addition to the extraction of impact forces, secondary impact forces, spray characteristics, and cavity formation, it is demonstrated that there is a combined critical length and entry velocity where the spray formation stops and the spray vanishes. It is also shown that the cavity and secondary impact do not occur under these circumstances. Moreover, it is concluded that for these particular cases, there is a maximum secondary impact force that occurs for the deadrises angles less than 20o

Asymmetric Water Entry of Twin Wedges with Different Deadrises, Heel Angles, and Wedge Separations using Finite Element Based Finite Volume Method and VOF

Asymmetric water entry of twin wedges is investigated for deadrise angles of 30 and 50 degrees, and heel angles of 5, 10, 15, and 20 degrees as well as wedge separation ratios of 1 and 2. Finite Element based Finite Volume method (FEM-FVM) is used in conjunction with Volume of Fluid (VOF) scheme for the targeted analyses. Free surface evolution and impact forces versus time are determined and comparisons of the maximum force of the wedges against each other are presented for all the considered cases. It is demonstrated that the impact force on the second wedge is always greater than the first one by a minimum of 6% and maximum of 146% which is a very significant increase in the impact force and may cause high accelerations and damage to the structure. It is also observed that the mentioned effects increase with decreasing deadrise angle and increasing heel angle

ESTIMATION OF WATER ENTRY FORCES, SPRAY PARAMETERS AND SECONDARY IMPACT OF FIXED WIDTH WEDGES AT EXTREME ANGLES USING FINITE ELEMENT BASED FINITE VOLUME AND VOLUME OF FLUID METHODS

In this paper, water entry of wedges with deadrise angles ranging from 10 to 80 degrees at two different velocities is simulated. Impact forces, spray parameters, cavity formation above the chine, and secondary impact forces due to the cavity formation are investigated with particular focus on the extreme angles. To this end, a two dimensional two-phase Finite-Element based Finite-Volume (FEM-FVM) code is developed and validated against experimental data with good compliance. Free surface modeling in this software is accomplished by applying Volume of Fluid (VOF) method. In addition to the extraction of impact forces, secondary impact forces, spray characteristics, and cavity formation, it is demonstrated that there is a combined critical length and entry velocity where the spray formation stops and the spray vanishes. It is also shown that the cavity and secondary impact do not occur under these circumstances. Moreover, it is concluded that for these particular cases, there is a maximum secondary impact force that occurs for the deadrises angles less than 20o