Entropy-based detached-eddy simulation of the airwake over a simple frigate shape

Zhao, Rui; Rong, Jian; Li, Haixu; Zhao, Pengcheng

doi:10.1177/1687814015616930

Cited by 8 publications

(2 citation statements)

References 19 publications

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“…Further, these structures interact with the shedding vortices from the edges of hangar roof and enforce additional downwash turbulence in the airwake. 30 Thus, it became necessary to gauge the uninterrupted cross-flow effect on SRD at initial stage. Therefore, the modified SFS2 geometry was used in the initial stage of investigations and then followed with SFS2 geometry.…”

Section: Background Of Sdi Modelmentioning

confidence: 99%

A conceptual method to assess ship-helicopter dynamic interface

Shukla

Singh

Sinha

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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The combined operation of a ship and a helicopter is ubiquitous in every naval organization. The operation of a ship in combination with the landing and take-off operations of a helicopter results in a very complex flow phenomenon. This is due to the presence of ship airwakes, strong velocity gradients and widely varying turbulence length scales. An accurate assessment of the resultant flow phenomena is an outstanding challenge for naval architects as well as researchers. A conceptual method to gain insight into the combined ship-helo flow phenomena over a helodeck is presented. The prime objective of this work is to develop an economical design tool employing both experimental as well as computational techniques to simulate the ship-helicopter coupled environment regime at early design stages reasonably well so as to ease the burden of expensive and risky sea trials. For this purpose, a simplified dynamic interface (SDI) model is proposed to investigate the coupled effects of ship airwake and helicopter rotor downwash. The paper reports a parametric analysis to study the coupled ship-helo airwake behaviour and its impact on helicopter fuselage over the ship helodeck for different ship speed regimes by the proposed SDI model. Further, an attempt has been made to set up preliminary design criteria to grade the ship-helicopter interface for ensuring minimum standards of safe helo operations. Finally, we discuss the impact of the coupled flow dynamics in terms of induced fuselage drag, cross-flow characteristics, rotor plane wake and velocity gradients existing over the helodeck region and evaluate the proposed design criteria.

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Section: Background Of Sdi Modelmentioning

confidence: 99%

A conceptual method to assess ship-helicopter dynamic interface

Shukla

Singh

Sinha

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…The flow topology of a frigate's flight deck is critical for flight operations; especially for quick take-off and landing of naval helicopters at various headwind conditions (see NATO (2017) guidelines). In this regard, several studies have been performed numerically and experimentally to predict the air-wake of ships and frigates (Wakefield et al (2002); Syms (2008); Forrest and Owen (2010); Herry (2010); Herry et al (2011); K€ a€ ari€ a et al (2013); Van Muijden et al (2013); Rui et al (2015); Mora (2014); Mora and Meseguer (2015); Vidales (2016); Orbay and Sezer-Uzol (2016); Gallas et al (2017); Shi et al (2017); Crozon et al (2018) and others). The flow past a frigate wake is analogous to that of a finite-width double-backward facing step (Tinney and Ukeiley (2009)), with the region behind the superstructure and the flight deck forming the top step, and the region behind the stern forming the bottom step.…”

Section: Introductionmentioning

confidence: 99%

Qualitative assessment of the bi-stable states in the wake of a finite-width double backward facing step

Rao

Zhang

Minelli

et al. 2019

Journal of Wind Engineering and Industrial Aerodynamics

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A B S T R A C TThe flow past a simplified frigate shape model which is analogous to a finite-width double backward facing step is investigated numerically using well-resolved large eddy simulations at Re ' 8 Â 10 4 . The geometric configuration of this model permits the occurrence of bi-stable flow states, with an asymmetrical flow topology being observed in the lateral midplane behind each step. In each flow state, the flow at the top step is anti-symmetrical to that observed on the bottom step, and the two flow states are anti-symmetrical to each other. Furthermore, incorporating a base cavity on the top step leads to the suppression of the asymmetrical flow topology on both the steps. The recirculation bubble formed by the downwash at each step is elongated when the base cavity is used, as compared to that observed in either of the two flow states, resulting in a decrease of the drag coefficient. In each of the two flow states, the unequal strength of the streamwise vortices close to the lateral edges on the top step has been identified as the likely cause of the asymmetrical flow on the bottom step.

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Modeling and Simulation of Ship–Helicopter Dynamic Interface: Method and Application

Cao

Qin

2022

Arch Computat Methods Eng

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Entropy-based detached-eddy simulation of the airwake over a simple frigate shape

Cited by 8 publications

References 19 publications

A conceptual method to assess ship-helicopter dynamic interface

A conceptual method to assess ship-helicopter dynamic interface

Qualitative assessment of the bi-stable states in the wake of a finite-width double backward facing step

Modeling and Simulation of Ship–Helicopter Dynamic Interface: Method and Application

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