The structure of the wake generated by a submarine model in yaw

Ashok, Anand; Buren, Tyler Van; Smits, Alexander J.

doi:10.1007/s00348-015-1997-4

Cited by 24 publications

(2 citation statements)

References 19 publications

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“…With increasing trip diameter, the location of the vortex pair moves up (increasing z) relative to the location of the stern, but this is most likely due to a slightly more leeward separation of the measurements on the 1:120 scale model, the trip-wire diameter was fixed at 1.6 mm to achieve adequate tripping without unduly distorting the wake evolution. It should be noted that the trip-wire sensitivity is more significant in yaw, and the 1.6 mm trip was the smallest size that gave mirror symmetry of the vortices in yaw (Ashok, Van Buren & Smits 2015).…”

Section: Wake Sensitivitymentioning

confidence: 97%

Asymmetries in the wake of a submarine model in pitch

2015

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Detailed velocity measurements in the wake of a body of revolution are reported for pitch angles up to 12 • , over an unprecedented range of Reynolds numbers (2.4 × 10 6 Re L 30 × 10 6 ). The body of revolution, an idealized submarine shape (DARPA SUBOFF), is mounted using a support that mimics a semi-infinite sail. The wake measurements at all pitch angles and Reynolds numbers reveal the presence of a pair of streamwise vortices of unequal strengths which tend to rotate around each other as they evolve downstream. Various attempts to perturb the upstream conditions on the body had no significant impact on the relative strength of the vortices. In addition, two different models, tested in two different wind tunnels, show similar asymmetries, and we propose that wake asymmetry appears to be a robust feature of this flow, a result previously only seen for sharp-nosed bodies at high angles of attack. It is also shown that the wake behaviour for x/D > 5, in terms of the streamwise mean velocity and turbulence intensity distributions, appears to become invariant with Reynolds number for Re L > 4.8 × 10 6 .

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Section: Wake Sensitivitymentioning

confidence: 97%

Asymmetries in the wake of a submarine model in pitch

2015

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“…Fu utilized a PIV (particle image velocimetry) system to characterize the flow field around a sting-mounted captive ONR (Office of Naval Research) Body-1 submarine model in a steady turn [4]. Jimenez and Ashok utilized a hot-wire system and an SPIV (stereo particle image velocimetry) system to measure the flow field around an axisymmetric DARPA (Defense Advanced Research Projects Agency) SUBOFF (Submarine Technology Program Office) model, respectively, and flow field experimental databases with different Reynolds numbers, pitches, and yaw angles were obtained [5][6][7][8][9][10]. Similar research works on the SUBOFF model were conducted by Khan [11] and Shokrallah [12].…”

Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation of the Flow around a Generic Submarine under Straight-Ahead and 10° Yaw Conditions

Chen,

Zhang,

Sun

et al. 2023

JMSE

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Aiming towards a better understanding of the flow field around a fully appended Joubert BB2 submarine model, and in order to complement the experimental investigations of the wake of the hydroplanes and sail, large eddy simulation (LES) with the dynamic Smagorinsky model was conducted. Three sets of grids with a maximum grid number of up to 228 million were designed to perform the LES simulation for the Joubert BB2 under 10° yaw conditions, with a freestream Reynolds number based on the local freestream velocity and a hull length of ReL = 2.2 × 107. Comparisons of the wake of the cruciform appendage were made with experiments to verify the computational accuracy and to examine the influence of the spatial resolution. A satisfactory result was more representative of the experiments with the improvement in grid spatial resolution. The evolution characteristics of three co-rotating vortices originating from the cruciform appendage under the most refined grid arrangement are further described in detail under straight-ahead and 10° yaw conditions. The comparison results show that, in the core-flow region, the resultant velocity, vorticity magnitude, and TKE were stronger and the wake was more complicated under 10° yaw conditions. Tip vortex tracking under 10° yaw conditions exhibited significant three-dimensional characteristics as the wake developed downstream.

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