Investigasi Hambatan Dan Seakeeping Warship Catamaran Menggunakan Simulasi Numerik (CFD) Dan Pengujian Eksperimen (EFD): Pengaruh Jarak Antar Lambung Dan Tunnel Clearance

Wulandari, Amalia Ika (2025) Investigasi Hambatan Dan Seakeeping Warship Catamaran Menggunakan Simulasi Numerik (CFD) Dan Pengujian Eksperimen (EFD): Pengaruh Jarak Antar Lambung Dan Tunnel Clearance. Doctoral thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Kapal katamaran dengan konfigurasi Flat Side Inside (FSI) semakin banyak diadopsi dalam transportasi, operasi militer, dan sektor kelautan lepas pantai karena keunggulannya dalam stabilitas dan efisiensi. Namun, interaksi hidrodinamika yang kompleks akibat gelombang antar lambung dan efek tekanan di area tunnel menjadikan analisis hambatan dan seakeeping sangat penting. Penelitian ini mengevaluasi pengaruh variasi jarak antar lambung (S/L) dan tinggi tunnel clearance (TC) terhadap karakteristik hidrodinamika kapal katamaran FSI melalui pendekatan numerik dan eksperimental. Metode yang digunakan mencakup simulasi numerik berbasis Computational Fluid Dynamics (CFD) dengan pendekatan RANS untuk analisis hambatan dan Boundary Element Method (BEM) untuk seakeeping, serta pengujian eksperimen (Experimental Fluid Dynamics / EFD) sebagai validasi. Hasil analisis terbaru menunjukkan bahwa urutan koefisien hambatan total (CT) dari yang tertinggi ke terendah adalah S/L 0,2, diikuti S/L 0,3, dan yang paling rendah adalah S/L 0,4, dengan CT tertinggi tetap tercatat pada Fr 0,5. Hal ini mengindikasikan bahwa jarak antar lambung yang lebih sempit memicu interferensi gelombang yang lebih kuat di area tunnel, meningkatkan tekanan dinamis dan memperbesar hambatan total. Sebaliknya, pada S/L 0,4, ruang antar lambung yang lebih lebar memungkinkan pola gelombang menyebar dan meredam interferensi, sehingga hambatan total menurun. Variasi tunnel clearance (TC) menunjukkan tren penurunan hambatan seiring peningkatan TC, dengan TC 0,9 menghasilkan CT terendah dalam rentangnya, karena interaksi langsung antara gelombang dan permukaan bawah wet deck dapat diminimalkan. Dari sisi seakeeping, respon gerakan (heave, pitch, dan roll) sangat dipengaruhi arah gelombang, kecepatan kapal, dan rasio S/L. Konfigurasi S/L 0,2 secara konsisten menghasilkan respon gerakan tertinggi karena ruang antar lambung sempit memperkuat interferensi gelombang di area dalam, sedangkan S/L 0,4 terbukti memberikan respon gerakan terendah, menunjukkan stabilitas terbaik di berbagai kondisi operasi. Pengaruh TC terhadap seakeeping relatif kecil, tetapi peningkatan TC ke 0,9 tetap memberikan sedikit penurunan amplitudo gerakan akibat peningkatan jarak bebas yang meredam gaya vertikal gelombang pada tunnel. Pada kondisi tanpa kecepatan, arah gelombang samping (90°) memicu heave dan roll tertinggi, sementara pitch mencapai puncak pada arah 180° (head seas). Seiring peningkatan kecepatan, pola respon gerakan bergeser ke arah gelombang depan-belakang (0° dan 180°), tetapi roll tetap dominan di gelombang samping karena gaya melintang. Analisis korelasi antara hambatan dan seakeeping diperkuat dengan pendekatan statistik ANOVA dan integrasi fuzzy logic. Hasil gabungan menunjukkan bahwa konfigurasi optimal yang memberikan kompromi terbaik antara hambatan rendah dan respon gerakan stabil tercapai pada S/L 0,4, TC 0,9, dan Fr 1,3. Pendekatan fuzzy logic digunakan untuk menyatukan hasil ANOVA hambatan dan seakeeping menjadi sistem pengambilan keputusan multi-kriteria yang adaptif, sehingga mendukung perancangan desain lambung yang lebih efisien, stabil, dan siap diterapkan dalam berbagai kondisi operasi kapal katamaran FSI.
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Catamarans with a Flat Side Inside (FSI) configuration are increasingly adopted in transportation, military operations, and offshore marine sectors due to their superior stability and efficiency. However, the complex hydrodynamic interactions caused by inter-hull wave interference and pressure effects in the tunnel area make resistance and seakeeping analysis crucial. This study evaluates the influence of variations in hull separation distance (S/L) and tunnel clearance (TC) on the hydrodynamic characteristics of FSI catamarans through both numerical and experimental approaches. The methods used include Computational Fluid Dynamics (CFD) based on the Reynolds-Averaged Navier-Stokes (RANS) equations for resistance analysis, Boundary Element Method (BEM) for seakeeping, and Experimental Fluid Dynamics (EFD) for validation. Recent analysis indicates that the order of total resistance coefficients (CT) from highest to lowest is S/L = 0.2, followed by S/L = 0.3, with the lowest CT at S/L = 0.4, where the highest CT consistently appears at Fr = 0.5. This suggests that narrower hull spacing intensifies wave interference within the tunnel area, increasing dynamic pressure and total resistance. Conversely, at S/L = 0.4, the wider inter-hull spacing allows the wave patterns to dissipate and reduces interference, thus lowering total resistance. Variation in tunnel clearance (TC) shows a decreasing trend in resistance with increasing TC, where TC = 0.9 yields the lowest CT within the tested range. This is attributed to the reduced direct interaction between waves and the underside of the wet deck. In terms of seakeeping, motion responses (heave, pitch, and roll) are significantly affected by wave direction, vessel speed, and S/L ratio. The S/L = 0.2 configuration consistently produces the highest motion responses due to strong wave interference in the narrow inner hull region, while S/L = 0.4 demonstrates the lowest responses, indicating superior stability across various operating conditions. The effect of TC on seakeeping is relatively minor, although an increase to TC = 0.9 slightly reduces motion amplitudes due to greater clearance damping vertical wave forces in the tunnel. Beam seas (90° wave heading) induce the highest heave and roll responses, while pitch peaks in head seas (180°). As speed increases, the motion response pattern shifts toward longitudinal wave directions (0° and 180°), although roll remains dominant under xiv beam seas due to transverse forces. Correlation analysis between resistance and seakeeping is strengthened using ANOVA and fuzzy logic approaches. The combined results indicate that the optimal configuration, providing the best tradeoff between low resistance and stable motion response, is achieved at S/L = 0.4, TC = 0.9, and Fr = 1.3. Fuzzy logic is employed to integrate ANOVA outcomes for resistance and seakeeping into an adaptive multi-criteria decision-making system, supporting the design of more efficient, stable, and operationally versatile FSI catamaran hulls.

Item Type:	Thesis (Doctoral)
Uncontrolled Keywords:	Kapal Perang Katamaran, Simulasi Numerik, Hambatan, Seakeeping, Warship Catamaran, Numerical Simulation, Resistance
Subjects:	V Naval Science > VM Naval architecture. Shipbuilding. Marine engineering > VM751 Resistance and propulsion of ships
Divisions:	Faculty of Marine Technology (MARTECH) > Ocean Engineering > 38001-(S3) PhD Thesis
Depositing User:	Amalia Ika Wulandari
Date Deposited:	05 Aug 2025 11:53
Last Modified:	05 Aug 2025 11:53
URI:	http://repository.its.ac.id/id/eprint/127096

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