Turbulence intensities in the near-wake of a semielliptical afterbody

Merz, Richard; Yi, Cao; Przirembel, C. E. G.

doi:10.2514/3.9564

Cited by 5 publications

(1 citation statement)

References 3 publications

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“…Jiménez et al (2010a,b) attributed it to the thick boundary layer developing along the stern of the DSub model. This is consistent with observations in earlier experiments by Patel, Nakayama & Damian (1974) and Merz, Yi & Przirembel (1986). In figure 14 the averaged turbulent kinetic energy, k, is shown at three different meridian planes up…”

Section: Bimodal Behaviour Of the Wake And Effect Of The Finssupporting

confidence: 89%

A numerical investigation of the wake of an axisymmetric body with appendages

Posa

Balaras

2016

J. Fluid Mech.

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We report wall-resolved large-eddy simulations of an axisymmetric body of revolution with appendages. The geometry is that of the DARPA SUBOFF body at 0 yaw angle and a Reynolds number equal to Re L = 1.2 × 10 6 (based on the free-stream velocity and the length of the body). The computational grid, composed of approximately 3 billion nodes, is designed to capture all essential flow features, including the turbulent boundary layers on the surface of the body. Our results are in good agreement with measurements available in the literature. It is shown that the wake of the body is affected mainly by the shear layer from the trailing edge of the fins and the turbulent boundary layer growing along the stern, while the influence of the wake of the sail is minimal. In agreement with the reference experiments, a bimodal behaviour for the turbulent stresses is observed in the wake. This is due to the displacement of the maximum of turbulent kinetic energy away from the wall along the surface of the stern, where the boundary layer is subjected to strong adverse pressure gradients. The junction flows, produced by the interaction of the boundary layer with the leading edge of the fins, enhance this bimodal pattern, feeding additional turbulence in the boundary layer and the downstream wake. The evolution of the wake towards selfsimilarity is also investigated up to nine diameters downstream of the tail. We found the mean flow approaches this condition, while its development is delayed by the wake of the appendages, especially by the flow coming from the tip of the fins. However, the width of the wake and its maximum momentum deficit follow the expected powerlaw behaviour on the side away from the sail. The second-order statistics, on the other hand, are still far from self-similarity, which is consistent with experimental observations in the literature.

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Section: Bimodal Behaviour Of the Wake And Effect Of The Finssupporting

confidence: 89%

A numerical investigation of the wake of an axisymmetric body with appendages

Posa

Balaras

2016

J. Fluid Mech.

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The Effects of Fins on the Intermediate Wake of a Submarine Model

Jiménez

Reynolds

Smits

2010

Journal of Fluids Engineering

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Results are presented on the behavior of the turbulent wake behind a submarine model for a range of Reynolds numbers based on the model length between 0.49×106 and 1.8×106, for test locations between 3 and 9 diameters downstream of the stern. The shape of the model emulates an idealized submarine, and tests were performed with and without stern fins. In the absence of fins, the velocity profile in planes away from the influence of the sail rapidly becomes self-similar and is well described by a function of exponentials. The fins create defects in the velocity profiles in the outer region of the wake, while yielding higher values of turbulence at locations corresponding to the tips of the fins. Measurements conducted in planes away from the midline plane show that the velocity profiles remain self-similar, while the shear stress profiles clearly show the effects of the necklace vortices trailing from the base of the fins.

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BOUNDARY LAYER-TRIPPING STUDIES ON CHARACTERISTICS OF NEAR-WAKE BEHIND A CAMBERlED AIRFOIL

Abdalla

1999

ERJ. Engineering Research Journal

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Turbulence intensities in the near-wake of a semielliptical afterbody

Abstract: = velocity fluctuation X = axial distance from base (positive = downstream, negative = upstream) Y = radial distance from centerline Subscripts oo = freestream condition

Cited by 5 publications

References 3 publications

A numerical investigation of the wake of an axisymmetric body with appendages

A numerical investigation of the wake of an axisymmetric body with appendages

The Effects of Fins on the Intermediate Wake of a Submarine Model

BOUNDARY LAYER-TRIPPING STUDIES ON CHARACTERISTICS OF NEAR-WAKE BEHIND A CAMBERlED AIRFOIL

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