Experimental investigation of airflow over helicopter platform of a polar icebreaker

Rahimpour, Mostafa; Oshkai, Peter

doi:10.1109/oceans-genova.2015.7271439

Cited by 1 publication

(3 citation statements)

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“…This is likely due to the fact that the mean velocity profile of the ABL cases continues to increase above the ship, while the unstimulated BL attains a constant (lower) maxmium (see left of figure 1a). In both ABL cases the separation region is also shortened consistent with [9] and this results in more intense low velocity regions close to the hangar (region 3). The ABLTC1 case appears to have the greatest reduction in separation region extent, possibly because the turbulence levels upstream and above the model are highest for this case.…”

Section: Resultsmentioning

confidence: 52%

“…However, most experimental studies on ship air-wakes are performed with uniform incoming flows [3,13], despite the importance of ABL in the air-wake behaviour being often cited [12,16]. A handful of studies that included simulated ABL conditions showed changes in the wake spatial structure and the level of turbulence fluctuation on the landing deck [5,9,15]. A simulation by Rosenfeld [10] further showed that the ship topside experiences lower velocity fluctuations when planetary boundary layer conditions are included.…”

Section: Introductionmentioning

confidence: 99%

“…There remain seemingly contradictory conclusions on the effects of the ABL on the ship air-wake over the Helicopter Landing Deck (HLD). An experimental investigation by Rahimpour & Oshkai [9] on the Canadian Coast Guard (CCG) model suggested that the lower incident velocity at the ship level (due to the shape of ABL velocity profile) results in a more confined recirculation zone. Higher fluctuations were also observed on the landing deck, which was attributed to the more significant turbulence level in the oncoming ABL flow.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An assessment of Atmospheric Boundary Layer Effects on the Ship Air–wake

Setiawan¹,

Kevin²,

Monty³

2020

Australasian Fluid Mechanics Conference (AFMC)

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The ship air-wake over the landing deck of a NATO-Generic Destroyer model is investigated experimentally to better understand the effects of the Atmospheric Boundary Layer (ABL) on the flow. Two methods of creating thick ABLs are employed: i. using a series of tripping devices in a typical wind tunnel; ii. by performing the test on a water surface in a wind-wave facility. In comparison with a smooth-wall (unstimulated) boundary layer, the wake of the ship is substantially modified for both ABL cases. The ABL increases the overall fluctuation levels over the landing deck, highlighting the importance of including an ABL in simulations or experiments. Specifically, we show that the streamwise fluctuation on the landing deck increases linearly with both the background turbulence and the reference mean velocity; a simple relationship is provided. We consider the sensitivities of the wake to ABL scaling (relative to ship height), noting that a thicker ABL will generally lead to lower fluctuation levels in the wake over the landing deck (in the absence of free stream turbulence intensity).

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Section: Resultsmentioning

confidence: 52%