The similarity of turbulent spots in subsonic boundary layers

Lange, H. C. de; Hogendoorn, C.J.; Steenhoven, A.A. van

doi:10.1016/s0735-1933(98)00020-7

Cited by 3 publications

(5 citation statements)

References 6 publications

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“…This increase appears to be consistent with the results of Zhong et al (2000), who also measured turbulent spots in water. However, this increase is lower than the peak heat transfer found by Clark et al (1994) and de Lange et al (1998), whose experiments in air measured spots with peak levels comparable to average levels in turbulent boundary layers. This discrepancy is probably a result of the difference in Prandtl numbers between the air and water experiments.…”

Section: Combined Flow Field and Surface Heat Transfer Datacontrasting

confidence: 57%

“…Further, Clark et al (1994) and Ching & LaGraff (1995) also found that the peak heat transfer is between 0.48U ∞ and 0.56U ∞ , which is consistent with the peak at ξ ≈ 0.5 in figure 9. In contrast, the heat-transfer measurements of de Lange et al (1998) and Zhong et al (2000) imply the leading and trailing edges of the heat transfer coincide with the leading and trailing edges of the flow structures within the spot. However, Zhong et al (2000) reported the leading-edge speed of the heat-transfer fluctuations to be 0.78U ∞ and, when the data is replotted in similarity coordinates, the peak surface-heat transfer speed is in the range 0.5 < ξ < 0.6.…”

Section: Combined Flow Field and Surface Heat Transfer Datamentioning

confidence: 80%

“…However, Zhong et al (2000) measured heat transfer levels in water that were lower than fully turbulent values. The results of de Lange et al (1998) and Zhong et al (2000) imply that the body of the spot is responsible for the maximum surface heat transfer and the calmed region of the spot has correspondingly little effect on surface heat transfer. However, it is difficult to establish a direct correlation between the flow field and the surface heat transfer.…”

Section: Introductionmentioning

confidence: 97%

“…The surface heat flux below turbulent spots has been directly measured by Clark, Jones & LaGraff (1994), Ching & LaGraff (1995) and de Lange, Hogendoorn & Steenhoven (1998). All three studies, performed in air, found that the maximum heat Figure 2.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Turbulent spot flow topology and mechanisms for surface heat transfer

Sabatino

Smith

2008

J. Fluid Mech.

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The properties of artificially initiated turbulent spots over a heated plate were investigated in a water channel. The instantaneous velocity field and surface Stanton number were simultaneously established using a technique that combines particle image velocimetry and thermochromic liquid crystal thermography. Several characteristics of a spot are found to be similar to those of a turbulent boundary layer. The spacing of the surface heat transfer streak patterns within the middle or ‘body’ of a turbulent spot are comparable to the low-speed streak spacing within a turbulent boundary layer. Additionally, the surface shear stress in the same region of a spot is also found to be comparable to a turbulent boundary layer. However, despite these similarities, the heat transfer within the spot body is found to be markedly less than the heat transfer for a turbulent boundary layer. In fact, the highest surface heat transfer occurs at the trailing or calmed region of a turbulent spot, regardless of maturity. Using a modified set of similarity coordinates, instantaneous two-dimensional streamlines suggest that turbulent spots entrain and subsequently recirculate warm surface fluid, thereby reducing the effective heat transfer within the majority of the spot. It is proposed that energetic vortices next to the wall, near the trailing edge of the spot body, are able to generate the highest surface heat transfer because they have the nearest access to cooler free-stream fluid.

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Section: Combined Flow Field and Surface Heat Transfer Datacontrasting

confidence: 57%

Section: Combined Flow Field and Surface Heat Transfer Datamentioning

confidence: 80%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Turbulent spot flow topology and mechanisms for surface heat transfer

Sabatino

Smith

2008

J. Fluid Mech.

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“…Despite a large scatter of the data a clear decrease of the lateral spreading with increasing Mach number was found. Measurements on naturally occurring turbulent spots in subsonic and supersonic boundary layers along flat plates were performed by Clark et al (1994), de Lange et al (1998 and Mee (2002). They detected turbulent spots and their growth from heat transfer measurements at the wall.…”

Section: Introductionmentioning

confidence: 99%

Growth of turbulent spots in high-speed boundary layers on a flat plate

Jocksch

Kleiser

2008

International Journal of Heat and Fluid Flow

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Combining the merits of experiments and numerics in flow stability analysis

Lange

2014

EPJ Web of Conferences

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Abstract. Boundary layer transition is a determining factor for drag and convective heat transfer for solid bodies moving through a fluid. The transition zone is known to depend on the level of main stream turbulence.Heat transfer experiments will show the different intermittency profiles. Numerical analysis will show the influence of velocity streaks. Detailed flow experiments are used to determine a possible breakdown mechanism, which, in its turn, will be studied in a model numerical analysis.

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The similarity of turbulent spots in subsonic boundary layers

Cited by 3 publications

References 6 publications

Turbulent spot flow topology and mechanisms for surface heat transfer

Turbulent spot flow topology and mechanisms for surface heat transfer

Growth of turbulent spots in high-speed boundary layers on a flat plate

Combining the merits of experiments and numerics in flow stability analysis

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