20.500.12556/RUL-182852 A numerical investigation into the thrust characteristics of the RAS-HA-X25 autonomous underwater vehicle through CFD-based simulation The rapid development of Autonomous Underwater Vehicles (AUVs) has increased the demand for propulsion systems that balance thrust density, hydrodynamic efficiency, and acoustic discretion. This study presents a comprehensive numerical investigation of the performance of the Blue Robotics T500 thruster, embedded within the RAS-HA-X25 AUV’s internal conduit. Using transient Computational Fluid Dynamics (CFD) within the OpenFOAM framework, this research assesses the propulsive characteristics of the thruster across six distinct outlet geometries, including convergent jet nozzles and multilobed “daisy” configurations. To improve computational efficiency for parametric design, a calibrated actuator disc model was developed and validated against resolved-rotor simulations, revealing a 15 % discrepancy attributed to tip leakage and hub vortex effects. Results show that at the operational advance ratio (J = 0.167), the 60 mm convergent nozzle is the optimal configuration for maximising thrust, achieving a peak net thrust of 42 N. In contrast, the daisy-type lobed geometries, while causing a 50 % reduction in absolute thrust compared to a standard cylindrical pipe, significantly homogenise the exit-plane velocity distribution and reduce swirl intensity. These findings indicate that lobed terminations provide a viable mechanism for reducing hydroacoustic signatures, offering a strategic “stealth” advantage for low-observable underwater platforms where acoustic discretion is prioritised over pure thrust density. This study establishes a robust methodology for optimising embedded propulsion modules in next-generation autonomous and hybrid underwater vehicles. Raziskovalni članek obravnava razvoj naprednih pogonskih sistemov za avtonomna podvodna vozila (AUV), ki omogočajo optimalno razmerje med potiskom, učinkovitostjo in nizko zvočno zaznavnostjo. Z uporabo numeričnih simulacij (CFD) so analizirane različne geometrije iztoka, ki vplivajo na zmogljivost in prikritost delovanja. Rezultati kažejo, da določene konfiguracije povečujejo potisk, druge pa pomembno zmanjšujejo akustični podpis vozila. To omogoča razvoj bolj prikritih in učinkovitih podvodnih sistemov. Raziskava neposredno podpira razvoj podvodnih dronov za nadzor, zaščito in varovanje pristanišča Koper. Poleg tega omogoča optimizacijo delovanja v kompleksnih podvodnih okoljih, kjer sta zanesljivost in avtonomija ključnega pomena. Prispeva tudi k večji tehnološki neodvisnosti in konkurenčnosti Slovenije na področju naprednih pomorskih in obrambnih tehnologij. propeller duct hydrodynamics BlueRobotics T500 Thruster outflow nozzle propeler obtočni kanal hidrodinamika potisnik BlueRobotics T500 iztočna šoba true false true Angleški jezik Slovenski jezik Članek v reviji 2026-05-25 17:32:59 2026-05-25 17:33:09 2026-05-26 08:46:54 0000-00-00 00:00:00 2026 0 0 Str. 1-27 no. 7 Vol. 14 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 533.662.2:629.014.9 2077-1312 10.3390/jmse14070600 272915459 jmse-14-00600-v2.pdf jmse-14-00600-v2.pdf 1 F0115DE5ACD773D159C7D5FFE8FD4950 f5bcdaea380b78c6a42b2648f665ff33fdf50843192ac94c15c7d45ba9c5d88f 08c0d611-5850-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=234454 https://www.mdpi.com/2077-1312/14/7/600 1 b33cc31f-584e-11f1-b0ab-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=234453 Fakulteta za pomorstvo in promet Fakulteta za strojništvo Fakulteta za elektrotehniko Fakulteta za računalništvo in informatiko 0 0 0