The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Toru Katayama - One of the best experts on this subject based on the ideXlab platform.
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Bilge Keel–free surface interaction and vortex shedding effect on roll damping
Journal of Marine Science and Technology, 2017Co-Authors: Burak Yıldız, Toru KatayamaAbstract:Prediction of the roll damping of a ship with bilge Keels using traditional techniques, such as Ikeda’s method, is no longer sufficient when the bilge Keels interact with the free surface. The discrepancies occurring between this method and actual roll damping are due to free surface interaction and vortex shedding, which are not considered in this method. Reynolds-averaged Navier–Stokes (RANS) solvers can be used to capture these effects, and the widely used Ikeda’s method can be modified. In this study, two-dimensional (2D) roll damping calculations for a hull section with bilge Keels, including the free surface effects, are calculated numerically and experimentally for different draft cases. The normal forces acting on the bilge Keels are calculated numerically to show the free surface effect on bilge Keel roll damping. The generated vortices and vortex shedding from the bilge Keels are analyzed to investigate the effect of the bilge Keels–free surface interaction on the roll damping coefficients. The results show that the RANS solver is capable of predicting the roll damping coefficients in good agreement with experimental results and can be further used to modify Ikeda’s method. It is concluded that the bilge Keel forces decrease when the bilge Keels interact with the free surface, whereas Ikeda’s method gives a constant value for each draft condition. The interaction of the bilge Keels and free surface affects the generation of the vorticity and vortex shedding from the bilge Keels.
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bilge Keel free surface interaction and vortex shedding effect on roll damping
Journal of Marine Science and Technology, 2017Co-Authors: Burak Yıldız, Toru KatayamaAbstract:Prediction of the roll damping of a ship with bilge Keels using traditional techniques, such as Ikeda’s method, is no longer sufficient when the bilge Keels interact with the free surface. The discrepancies occurring between this method and actual roll damping are due to free surface interaction and vortex shedding, which are not considered in this method. Reynolds-averaged Navier–Stokes (RANS) solvers can be used to capture these effects, and the widely used Ikeda’s method can be modified. In this study, two-dimensional (2D) roll damping calculations for a hull section with bilge Keels, including the free surface effects, are calculated numerically and experimentally for different draft cases. The normal forces acting on the bilge Keels are calculated numerically to show the free surface effect on bilge Keel roll damping. The generated vortices and vortex shedding from the bilge Keels are analyzed to investigate the effect of the bilge Keels–free surface interaction on the roll damping coefficients. The results show that the RANS solver is capable of predicting the roll damping coefficients in good agreement with experimental results and can be further used to modify Ikeda’s method. It is concluded that the bilge Keel forces decrease when the bilge Keels interact with the free surface, whereas Ikeda’s method gives a constant value for each draft condition. The interaction of the bilge Keels and free surface affects the generation of the vorticity and vortex shedding from the bilge Keels.
Mohammad Imron - One of the best experts on this subject based on the ideXlab platform.
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stabilitas sampan terbuat dari ember cat bekas dengan bilge Keel pada sudut 30 dan 45 derajat
Jurnal Teknologi Perikanan dan Kelautan, 2017Co-Authors: Muhammad Agam Thahir, Budhi Hascaryo Iskandar, Mohammad ImronAbstract:Used-paint-buckets can be used as an alternative material instead of wood or fibreglass in contructing a canoe. Its light weight and easy to roll, even in relatively calm water, showing of the low stability. In order to increase its stability, bilge Keels were applied in this canoe. The purpose of this study is to obtain the impact of bilge Keels application at different angles in order to increase stability. The dimension of the canoe was: the length (LOA) 3.15 m; width (B) 0.64 m; and depth (D) 0.30 m. Numerical simulation method to obtain the value of some stability parameter and seakeeping (pitching, heaving, and rolling) was used in this study. For the wave factor, JONSWAP wave spectrum was used as an input in this numerical simulation. The analysis result showed that there were differences in the stability, indicated by the value of righting arm on the bilge Keel with 30 and 45 degree as much as 0.001 m. Bilge Keel with an angle of 30 degrees give better stability value compare to 45 degrees. From the analysis of the response amplitude operator (RAO) showed that the rolling, pithcing and heaving motion of the canoe was remain in the normal.
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STABILITY OF A USED-PAINT-BUCKET BOAT EQUIPPED WITH 30 AND 45 DEGREE ANGEL BILGE KeelS
2014Co-Authors: Muhammad Agam Thahir, Budhi Hascaryo Iskandar, Mohammad ImronAbstract:Used-paint-buckets can be used as an alternative material instead of wood or fibreglass in contructing a canoe. Its light weight and easy to roll, even in relatively calm water, showing of the low stability. In order to increase its stability, bilge Keels were applied in this canoe. The purpose of this study is to obtain the impact of bilge Keels application at different angles in order to increase stability. The dimension of the canoe was: the length ( LOA ) 3.15 m; width ( B ) 0.64 m; and depth ( D) 0.30 m. Numerical simulation method to obtain the value of some stability parameter and seakeeping (pitching, heaving, and rolling) was used in this study. For the wave factor, JONSWAP wave spectrum was used as an input in this numerical simulation. The analysis result showed that there were differences in the stability, indicated by the value of righting arm on the bilge Keel with 30 and 45 degree as much as 0.001 m. Bilge Keel with an angle of 30 degrees give better stability value compare to 45 degrees. From the analysis of the response amplitude operator ( RAO ) showed that the rolling, pithcing and heaving motion of the canoe was remain in the normal.
Imron Mohammad - One of the best experts on this subject based on the ideXlab platform.
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STABILITAS SAMPAN TERBUAT DARI EMBER CAT BEKAS DENGAN BILGE Keel PADA SUDUT 30 DAN 45 DERAJAT
'Jurnal Teknologi Perikanan dan Ilmu Kelautan', 2017Co-Authors: Thahir, Muhammad Agam, Iskandar, Budhi H., Imron MohammadAbstract:Used-paint-buckets can be used as an alternative material instead of wood or fibreglass in contructing a canoe. Its light weight and easy to roll, even in relatively calm water, showing of the low stability. In order to increase its stability, bilge Keels were applied in this canoe. The purpose of this study is to obtain the impact of bilge Keels application at different angles in order to increase stability. The dimension of the canoe was: the length (LOA) 3.15 m; width (B) 0.64 m; and depth (D) 0.30 m. Numerical simulation method to obtain the value of some stability parameter and seakeeping (pitching, heaving, and rolling) was used in this study. For the wave factor, JONSWAP wave spectrum was used as an input in this numerical simulation. The analysis result showed that there were differences in the stability, indicated by the value of righting arm on the bilge Keel with 30 and 45 degree as much as 0.001 m. Bilge Keel with an angle of 30 degrees give better stability value compare to 45 degrees. From the analysis of the response amplitude operator (RAO) showed that the rolling, pithcing and heaving motion of the canoe was remain in the normal.Ember cat bekas dapat dimanfaatkan sebagai alternatif pengganti kayu yang semakin sulit diperoleh dan pengganti bahan serat fiber yang tidak murah dalam pembuatan sampan. Namun sampan ini memiliki kekurangan, yakni stabilitasnya yang rendah. Bobotnya yang ringan membuat sampan mudah oleng meskipun hanya beroperasi di perairan yang relatif tenang. Oleh karenanya instalasi sirip peredam oleng (bilge Keel) diharapkan dapat meningkatkan stablitas sampan ini. Tujuan penelitian ini adalah untuk mendapatkan nilai stabililitas sampan dengan instalasi bilge Keel pada sudut yang berbeda dalam rangka mendapatkan stabilitas sampan yang baik. Ukuran sampan yang dijadikan obyek dalam penelitian ini adalah panjang (LOA) 3,15m; lebar (B) 0,64m; dalam (D) 0,30m. Metode simulasi numerik untuk mendapatkan nilai stabilitas serta beberapa parameter seakeeping (pitching, roling dan heaving) digunakan dalam penelitian ini dengan bantuan perangkat lunak yang sesuai. Untuk faktor gelombang, spektrum gelombang JONSWAP digunakan sebagai inputan dalam simulasi numerik. Hasil analisis menunjukkan bahwa terdapat perbedaan stabilitas yang ditunjukkan oleh nilai lengan GZ (righting arm) pada sampan yang dipasangi bilge Keel dengan sudut 30 dan 45 derajat sebesar 0,001 m. Bilge Keel dengan sudut 30 derajat memberikan nilai stabilitas yang lebih besar dibandingkan dengan sudut 45 derajat. Dari analisis response amplitude operator (RAO) menunjukkan bahwa dengan inputan spektrum gelombang JONSWAP, gerakan rolling, pithcing dan heaving sampan masih berada pada rentang norma
Burak Yıldız - One of the best experts on this subject based on the ideXlab platform.
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Bilge Keel–free surface interaction and vortex shedding effect on roll damping
Journal of Marine Science and Technology, 2017Co-Authors: Burak Yıldız, Toru KatayamaAbstract:Prediction of the roll damping of a ship with bilge Keels using traditional techniques, such as Ikeda’s method, is no longer sufficient when the bilge Keels interact with the free surface. The discrepancies occurring between this method and actual roll damping are due to free surface interaction and vortex shedding, which are not considered in this method. Reynolds-averaged Navier–Stokes (RANS) solvers can be used to capture these effects, and the widely used Ikeda’s method can be modified. In this study, two-dimensional (2D) roll damping calculations for a hull section with bilge Keels, including the free surface effects, are calculated numerically and experimentally for different draft cases. The normal forces acting on the bilge Keels are calculated numerically to show the free surface effect on bilge Keel roll damping. The generated vortices and vortex shedding from the bilge Keels are analyzed to investigate the effect of the bilge Keels–free surface interaction on the roll damping coefficients. The results show that the RANS solver is capable of predicting the roll damping coefficients in good agreement with experimental results and can be further used to modify Ikeda’s method. It is concluded that the bilge Keel forces decrease when the bilge Keels interact with the free surface, whereas Ikeda’s method gives a constant value for each draft condition. The interaction of the bilge Keels and free surface affects the generation of the vorticity and vortex shedding from the bilge Keels.
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bilge Keel free surface interaction and vortex shedding effect on roll damping
Journal of Marine Science and Technology, 2017Co-Authors: Burak Yıldız, Toru KatayamaAbstract:Prediction of the roll damping of a ship with bilge Keels using traditional techniques, such as Ikeda’s method, is no longer sufficient when the bilge Keels interact with the free surface. The discrepancies occurring between this method and actual roll damping are due to free surface interaction and vortex shedding, which are not considered in this method. Reynolds-averaged Navier–Stokes (RANS) solvers can be used to capture these effects, and the widely used Ikeda’s method can be modified. In this study, two-dimensional (2D) roll damping calculations for a hull section with bilge Keels, including the free surface effects, are calculated numerically and experimentally for different draft cases. The normal forces acting on the bilge Keels are calculated numerically to show the free surface effect on bilge Keel roll damping. The generated vortices and vortex shedding from the bilge Keels are analyzed to investigate the effect of the bilge Keels–free surface interaction on the roll damping coefficients. The results show that the RANS solver is capable of predicting the roll damping coefficients in good agreement with experimental results and can be further used to modify Ikeda’s method. It is concluded that the bilge Keel forces decrease when the bilge Keels interact with the free surface, whereas Ikeda’s method gives a constant value for each draft condition. The interaction of the bilge Keels and free surface affects the generation of the vorticity and vortex shedding from the bilge Keels.
Muhammad Agam Thahir - One of the best experts on this subject based on the ideXlab platform.
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stabilitas sampan terbuat dari ember cat bekas dengan bilge Keel pada sudut 30 dan 45 derajat
Jurnal Teknologi Perikanan dan Kelautan, 2017Co-Authors: Muhammad Agam Thahir, Budhi Hascaryo Iskandar, Mohammad ImronAbstract:Used-paint-buckets can be used as an alternative material instead of wood or fibreglass in contructing a canoe. Its light weight and easy to roll, even in relatively calm water, showing of the low stability. In order to increase its stability, bilge Keels were applied in this canoe. The purpose of this study is to obtain the impact of bilge Keels application at different angles in order to increase stability. The dimension of the canoe was: the length (LOA) 3.15 m; width (B) 0.64 m; and depth (D) 0.30 m. Numerical simulation method to obtain the value of some stability parameter and seakeeping (pitching, heaving, and rolling) was used in this study. For the wave factor, JONSWAP wave spectrum was used as an input in this numerical simulation. The analysis result showed that there were differences in the stability, indicated by the value of righting arm on the bilge Keel with 30 and 45 degree as much as 0.001 m. Bilge Keel with an angle of 30 degrees give better stability value compare to 45 degrees. From the analysis of the response amplitude operator (RAO) showed that the rolling, pithcing and heaving motion of the canoe was remain in the normal.
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STABILITY OF A USED-PAINT-BUCKET BOAT EQUIPPED WITH 30 AND 45 DEGREE ANGEL BILGE KeelS
2014Co-Authors: Muhammad Agam Thahir, Budhi Hascaryo Iskandar, Mohammad ImronAbstract:Used-paint-buckets can be used as an alternative material instead of wood or fibreglass in contructing a canoe. Its light weight and easy to roll, even in relatively calm water, showing of the low stability. In order to increase its stability, bilge Keels were applied in this canoe. The purpose of this study is to obtain the impact of bilge Keels application at different angles in order to increase stability. The dimension of the canoe was: the length ( LOA ) 3.15 m; width ( B ) 0.64 m; and depth ( D) 0.30 m. Numerical simulation method to obtain the value of some stability parameter and seakeeping (pitching, heaving, and rolling) was used in this study. For the wave factor, JONSWAP wave spectrum was used as an input in this numerical simulation. The analysis result showed that there were differences in the stability, indicated by the value of righting arm on the bilge Keel with 30 and 45 degree as much as 0.001 m. Bilge Keel with an angle of 30 degrees give better stability value compare to 45 degrees. From the analysis of the response amplitude operator ( RAO ) showed that the rolling, pithcing and heaving motion of the canoe was remain in the normal.