Numerical procedure for Pre-Swirl Stator structural integrity evaluation

Bakica, Andro; Vladimir, Nikola; Malenica, Šime; Im, Hong-Il

doi:10.1016/j.oceaneng.2022.111698

Cited by 7 publications

(3 citation statements)

References 24 publications

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“…The viscous flow CFD numerical simulation, applied in various research fields [23][24][25][26][27][28][29][30], is based on the RANS (Reynolds-averaged Navier-Stokes) equations in the present research. The mass conservation continuity equation and the momentum conservation governing equation of incompressible fluid are as follows:…”

Section: Cfd Methods and Control Model 21 Rans Equationsmentioning

confidence: 99%

Mechanism of Speed Loss Reduction and Propulsion Efficiency Improvement of ONR Tumblehome with Active-Controlled Stern Flaps in Resonance Waves

Zhang,

Du,

et al. 2024

JMSE

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The stern flap is a practical hull appendage equipment that enhances ship navigation performance and saves energy. The existing studies mainly focus on the fixed stern flap, other than an actively controlled one, so it is worth further exploring its effect and mechanism. By implanting the PID controller to the stern flap, this paper proposed a free-running CFD model on the ONRT (the Office of Naval Research Tumblehome) ship coupled with the active-controlled stern flap to investigate the hydrodynamic performance in resonance waves. The free-running performance in calm water and regular waves is numerically researched and verified versus the experimental and referenced results. Then, the effect of different PID coefficients and control strategies of the stern flap on the traveling speed, attitudes, and propulsion performance under the resonance wave condition is conducted, and the influence mechanism is explored. The results show that adopting a fixed flap controller and PID controller can reduce the original speed loss by 4.2% and 6.9%, respectively, and increase the average propulsive efficiency of the propeller by 1.0% and 1.4%, respectively. Further analysis reveals that the global effect of the suppressed motion attitudes due to the installation of the fixed flap effectively contributes to the resistance reduction. However, the local effect of the stern flap increases the resistance due to interaction with the propeller and stern. The PID-controlled stern flap exhibits similar average attitudes compared to the fixed one, which means the resistance reduction of the global effect is kept the same, and the active stern flap further improves the stern flow field, where the resistance increment of the local effect is weakened, enhancing the traveling speed and improving the propulsion efficiency.

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Section: Cfd Methods and Control Model 21 Rans Equationsmentioning

confidence: 99%

Mechanism of Speed Loss Reduction and Propulsion Efficiency Improvement of ONR Tumblehome with Active-Controlled Stern Flaps in Resonance Waves

Zhang,

Du,

et al. 2024

JMSE

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“…As it seems, to evaluate the wave loads properly, the most important factors are the definition of the DLP (variable to maximize), the evaluation of the critical cases and their correlated Equivalent Design Waves (EDWs), and their simulation in a more complex, higher order environment. The most complete design proposal with respect to wave loads is presented in [38]. The DLP is defined as the hybrid lift force using potential method for the perturbed component and non-linear method for the steady-state component.…”

Section: Design Procedures For Energy Saving Devicesmentioning

confidence: 99%

“…Structural integrity evaluation procedure for ship appendages [38] Slika 8. Postupak za analizu integriteta konstrukcije brodskih privjesaka[38]…”

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Hydro-structural issues in the design of energy saving devices for ships

Bakica,

Vladimir,

Senjanović

2023

Rad Hrvatske akademije znanosti i umjetnosti

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The shipping sector is currently under growing pressure concerning the GHGs emission restriction prescribed by the International Maritime Organization (IMO). Improving the efficiency of the fleet has always been an attractive subject to the shipowners, but with the new regulations, the reduction in fossil fuel consumption has switched from optional economic benefit to a rule. One of the ways for the ship to comply with the new regulations is by installing or retrofitting Energy Saving Devices (ESDs). The ESDs exploit the axial and rotational energy losses inevitably produced by the propeller operation. The ESDs differ in shape, position and kind of energy to be recovered. This article gives an overview of the current trends and practices in the field of the ESDs, along with their classification and type of operation. Furthermore, besides the hydrodynamic design, which still holds the primary importance, structural issues are also addressed, since this subject is rarely investigated in the literature. Given the complex flow field of the ESDs influenced by propeller, ship motions, wake field and waves, applicability of numerical models is described in detail, whereby the state-of-the-art approaches are clearly highlighted. Overall, the ESDs are expected to further mature in the future given the rigid rules, the promising potential of efficiency improvements they offer and the lowcost of installation.

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