Study on the Effect of Two-Dimensional Helicopter V-buoy's Way of Water Entry on Water Impact
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摘要
To analyze the effect of the way of water entry on water impact, the FLUENT software was adopted to simulate a two-dimensional(2D) helicopter V-buoy's free fall and forced fall at a constant velocity. Combining with the UDF program and the dynamic mesh model, the standard k-ε turbulence model was used and the VOF technique was adopted to capture free surface. The physical parameters such as velocity and force were calculated and compared with those results of boundary element method with good agreement obtained. It was found that the force of 2D V-buoy at a constant velocity was much greater than that in free fall motion. Meanwhile, the maximum pressure coefficients C_(pmax) in both cases were almost equal and the dimensionless water-entry depths y' corresponding to C_(pmax) were also similar.
To analyze the effect of the way of water entry on water impact, the FLUENT software was adopted to simulate a two-dimensional(2D) helicopter V-buoy's free fall and forced fall at a constant velocity. Combining with the UDF program and the dynamic mesh model, the standard k-ε turbulence model was used and the VOF technique was adopted to capture free surface. The physical parameters such as velocity and force were calculated and compared with those results of boundary element method with good agreement obtained. It was found that the force of 2D V-buoy at a constant velocity was much greater than that in free fall motion. Meanwhile, the maximum pressure coefficients C_(pmax) in both cases were almost equal and the dimensionless water-entry depths y' corresponding to C_(pmax) were also similar.
To analyze the effect of the way of water entry on water impact, the FLUENT software was adopted to simulate a two-dimensional(2D) helicopter V-buoy's free fall and forced fall at a constant velocity. Combining with the UDF program and the dynamic mesh model, the standard k-ε turbulence model was used and the VOF technique was adopted to capture free surface. The physical parameters such as velocity and force were calculated and compared with those results of boundary element method with good agreement obtained. It was found that the force of 2D V-buoy at a constant velocity was much greater than that in free fall motion. Meanwhile, the maximum pressure coefficients C_(pmax) in both cases were almost equal and the dimensionless water-entry depths y' corresponding to C_(pmax) were also similar.
引文
[1] Jiang X W.Study of Some Key Problems on Helicopter Emergency Dipping Water Experiment.Wuhan:Wuhan University of Technology,2010.
[2]Li T,Li M Q,Wu J H.Helicopter ditching scale model test methods.Computer and Digital Engineering,2015,10:1790-1890.DOI:10.3969/j.issn.1672-9722.2015.10.015.
[3]Chen L X,Wang Z Z,Ma Y J.Estimation method for the distribution of ditching loads and pressures for helicopters with V bottom.Helicopter Technique,2014,2:5-9.DOI:10.3969/j.issn.1673-1220.2014.02.002.
[4]Ma Y J,Wang Z Z,Chen L X.Estimation of impact loads and pressure distribution of a flat-plate helicopter.Helicopter Technique,2014,1:1-5.DOI:10.3969/j.issn.1673-1220.2014.01.001.
[5]Yuan L B,Kang M.Simulation of helicopter impacting on calm water.Helicopter Technique,2016,1:15-21.DOI:10.3969/j.issn.1673-1220.2016.02.004.
[6]Sun J H,Zhou T,Li M Q,et al.Numerical analysis of emergent airbag deployment and ditching crashworthiness process .Journal of Nanjing University of Aeronautics & Astronautics,2012(5):713-717.DOI:10.16356/j.1005-2615.2012.05.019.
[7]Zhang J,Zhang Z R,Hong F W .Numerical simulation of initial flow of wedge entry.Journal of Ship Mechanics,2003,7(4):28-35.DOI:10.3969/ j.issn.1007-7294.2003.04.005.
[8]Wu Guoxiong .Numerical simulation for water entry of a wedge at varying speed by a high order boundary element method.Journal of Marine Science and Application,2012,11(2):143-149.DOI:10.1007/s11804-012-1116-3.
[9]Wu G X,Sun H,He Y S.Numerical simulation and experimental study of water entry of a wedge in free fall motion.Journal of Fluids and Structures,2004,19(3):277-289.DOI:10.1016/j.jfluidstructs.2004.01.001.
[10]Xu G D,Duan W Y,Wu G X .Numerical simulation of water entry of a cone in free-fall motion.Quarterly Journal of Mechanics and Applied Mathematics,2011,64(1):265-285.DOI:10.1093/qjmam/hbr003.
[11]Xu G D,Duan W Y,Wu G X.Simulation of water entry of a wedge through free fall in three degrees of freedom.Proceeding of Royal Society A,2010,466:2219-2239.DOI:10.1098/rspa.2009.0614.
[12]Xu G D,Duan W Y,Wu G X.Numerical simulation of oblique water entry of an asymmetrical wedge.Ocean Engineering,2008,35(16):1597-1603.DOI:10.1016/j.oceanng.2008.08.002.
[13]Wang F J.The Analysis of Computational Fluid Dynamics— The Theory and Applications of CFD Software.Beijing:Tsinghua University Press,2004.126-130.
[14]Faltinsen OM.Hydrodynamics of High-speed Marine Vehicles.Beijing:National Defense Industry Press,2007.510-519.
[15]Chen Qingtong,Ni Baoyu,Chen Shuping,et al.Numerical simulation of the water entry of a structure in free fall motion.J.Marine Sci.Appl.,2014,13(2):173-177.DOI:10.1007/s11804-014-1242-1.
[16]Yettou E-M,Desrochers A,Champoux Y.Experimental study on the water impact of a symmetrical wedge.Fluid Dynamics Research,2006,38(1):47-66.DOI:10.1016/j.fluiddyn.2005.09.003.
[2]Li T,Li M Q,Wu J H.Helicopter ditching scale model test methods.Computer and Digital Engineering,2015,10:1790-1890.DOI:10.3969/j.issn.1672-9722.2015.10.015.
[3]Chen L X,Wang Z Z,Ma Y J.Estimation method for the distribution of ditching loads and pressures for helicopters with V bottom.Helicopter Technique,2014,2:5-9.DOI:10.3969/j.issn.1673-1220.2014.02.002.
[4]Ma Y J,Wang Z Z,Chen L X.Estimation of impact loads and pressure distribution of a flat-plate helicopter.Helicopter Technique,2014,1:1-5.DOI:10.3969/j.issn.1673-1220.2014.01.001.
[5]Yuan L B,Kang M.Simulation of helicopter impacting on calm water.Helicopter Technique,2016,1:15-21.DOI:10.3969/j.issn.1673-1220.2016.02.004.
[6]Sun J H,Zhou T,Li M Q,et al.Numerical analysis of emergent airbag deployment and ditching crashworthiness process .Journal of Nanjing University of Aeronautics & Astronautics,2012(5):713-717.DOI:10.16356/j.1005-2615.2012.05.019.
[7]Zhang J,Zhang Z R,Hong F W .Numerical simulation of initial flow of wedge entry.Journal of Ship Mechanics,2003,7(4):28-35.DOI:10.3969/ j.issn.1007-7294.2003.04.005.
[8]Wu Guoxiong .Numerical simulation for water entry of a wedge at varying speed by a high order boundary element method.Journal of Marine Science and Application,2012,11(2):143-149.DOI:10.1007/s11804-012-1116-3.
[9]Wu G X,Sun H,He Y S.Numerical simulation and experimental study of water entry of a wedge in free fall motion.Journal of Fluids and Structures,2004,19(3):277-289.DOI:10.1016/j.jfluidstructs.2004.01.001.
[10]Xu G D,Duan W Y,Wu G X .Numerical simulation of water entry of a cone in free-fall motion.Quarterly Journal of Mechanics and Applied Mathematics,2011,64(1):265-285.DOI:10.1093/qjmam/hbr003.
[11]Xu G D,Duan W Y,Wu G X.Simulation of water entry of a wedge through free fall in three degrees of freedom.Proceeding of Royal Society A,2010,466:2219-2239.DOI:10.1098/rspa.2009.0614.
[12]Xu G D,Duan W Y,Wu G X.Numerical simulation of oblique water entry of an asymmetrical wedge.Ocean Engineering,2008,35(16):1597-1603.DOI:10.1016/j.oceanng.2008.08.002.
[13]Wang F J.The Analysis of Computational Fluid Dynamics— The Theory and Applications of CFD Software.Beijing:Tsinghua University Press,2004.126-130.
[14]Faltinsen OM.Hydrodynamics of High-speed Marine Vehicles.Beijing:National Defense Industry Press,2007.510-519.
[15]Chen Qingtong,Ni Baoyu,Chen Shuping,et al.Numerical simulation of the water entry of a structure in free fall motion.J.Marine Sci.Appl.,2014,13(2):173-177.DOI:10.1007/s11804-014-1242-1.
[16]Yettou E-M,Desrochers A,Champoux Y.Experimental study on the water impact of a symmetrical wedge.Fluid Dynamics Research,2006,38(1):47-66.DOI:10.1016/j.fluiddyn.2005.09.003.