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Date Published: 15/09/2026
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DOI: 10.51316/jst.192.ssad.2026.36.3.8
Issue
Vol. 36 No. 3 (2026): Journal of Science and Technology - Smart Systems and Devices 2026 (9/2026)
Section
Research article
How to Cite
Bui Thanh, D., Ngo Van, H., & Ikeda, Y. (2026). Effect of Length-to-Diameter Ratio on the Hydrodynamic Resistance of an Autonomous Underwater Vehicle at Constant Displacement: A Validated Computational Fluid Dynamics Study. Smart Systems and Devices, 36(3), 067-073. https://doi.org/10.51316/jst.192.ssad.2026.36.3.8

Effect of Length-to-Diameter Ratio on the Hydrodynamic Resistance of an Autonomous Underwater Vehicle at Constant Displacement: A Validated Computational Fluid Dynamics Study

Danh Bui Thanh1,2, , He Ngo Van1, Yoshiho Ikeda3
1 Hanoi University of Science and Technology, Ha Noi, Vietnam
2 Vietnam Maritime University, Hai Phong, Vietnam
3 Osaka Metropolitan University, Osaka, Japan

Main Article Content

Abstract

This paper examines the influence of the hull length-to-diameter ratio (L/D) on the hydrodynamic resistance of a generic axisymmetric AUV, represented by the DARPA SUBOFF bare hull. Three-dimensional steady Reynolds–averaged Navier–Stokes (RANS) simulations were conducted in STAR-CCM+ using the shear-stress transport (SST) k–ω turbulence model. The numerical procedure was validated against the SUBOFF towing-tank data of Liu and Huang: after a grid-independence study, the predicted resistance differs from the measurements by up to 3.1% across six forward speeds (1.27% at the reference condition). A family of five hulls spanning L/D = 6.44–11.76 was then generated by affine scaling at constant displacement, and each hull was simulated at six forward speeds. At every speed the resistance, expressed through a volumetric drag coefficient, has a minimum at L/D = 8.57, with off-optimum penalties below about 2%; the coefficient decreases with increasing Reynolds number. A slight change in the relative ranking of the off-optimum hulls was observed between low and high speeds, suggesting a shift in the balance between frictional and pressure-related resistance mechanisms. The findings provide quantitative guidance for selecting the slenderness of axisymmetric AUV hulls.

Keywords

AUV, length-to-diameter ratio, hydrodynamic resistance, RANS.

Article Details

Creative Commons License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

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