## Abstract

The experimental results for an equilibrium type boundary layer in a strong adverse pressure gradient flow are reported. The measurements show that similarity in the mean flow and the turbulent stresses has been achieved over a substantial streamwise distance where the skin friction coefficient is kept at a low, constant level. Although the Reynolds stress distribution across the layer is entirely different from the flow at zero pressure gradient, the ratios between the different turbulent stress components were found to be similar, showing that the mechanism for distributing the turbulent energy between the different components remains unaffected by the mean flow pressure gradient. Close to the surface the gradient of the mixing length was found to increase from 0.41 to 0.78. This is almost twice as high as for the zero pressure gradient case. The multi-point measurements indicated strong effects of the pressure gradient on the turbulent structure of the boundary layer. The average inclination from the wall in the (x, y) plane was found to be much more constant (about 20 degrees) through the layer than in the zero pressure gradient case. The length scales associated with the two-point correlations of the velocity fluctuations increased much faster with respect
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## Citation Formats

Skaare, P E.
Experimental investigation of an equilibrium boundary layer in strong adverse pressure gradient.
Norway: N. p.,
1994.
Web.

Skaare, P E.
Experimental investigation of an equilibrium boundary layer in strong adverse pressure gradient.
Norway.

Skaare, P E.
1994.
"Experimental investigation of an equilibrium boundary layer in strong adverse pressure gradient."
Norway.

@misc{etde_10110822,

title = {Experimental investigation of an equilibrium boundary layer in strong adverse pressure gradient}

author = {Skaare, P E}

abstractNote = {The experimental results for an equilibrium type boundary layer in a strong adverse pressure gradient flow are reported. The measurements show that similarity in the mean flow and the turbulent stresses has been achieved over a substantial streamwise distance where the skin friction coefficient is kept at a low, constant level. Although the Reynolds stress distribution across the layer is entirely different from the flow at zero pressure gradient, the ratios between the different turbulent stress components were found to be similar, showing that the mechanism for distributing the turbulent energy between the different components remains unaffected by the mean flow pressure gradient. Close to the surface the gradient of the mixing length was found to increase from 0.41 to 0.78. This is almost twice as high as for the zero pressure gradient case. The multi-point measurements indicated strong effects of the pressure gradient on the turbulent structure of the boundary layer. The average inclination from the wall in the (x, y) plane was found to be much more constant (about 20 degrees) through the layer than in the zero pressure gradient case. The length scales associated with the two-point correlations of the velocity fluctuations increased much faster with respect to the distance from the wall. In the bulk part of the layer the length scales were comparable to the length scales found in the zero pressure gradient layer, except for the streamwise length scale of the two-point correlation which was approximately half the length. Similarity in the triple correlation was also found to be good. The correlations show that there is a considerable diffusion of turbulent energy from the central part of the boundary layer towards the wall. The diffusion mechanism is caused by a second peak in the turbulence production, located at y/{delta} to be about 0.45. This production was for the present case almost as strong as the production found near the wall.}

place = {Norway}

year = {1994}

month = {Dec}

}

title = {Experimental investigation of an equilibrium boundary layer in strong adverse pressure gradient}

author = {Skaare, P E}

abstractNote = {The experimental results for an equilibrium type boundary layer in a strong adverse pressure gradient flow are reported. The measurements show that similarity in the mean flow and the turbulent stresses has been achieved over a substantial streamwise distance where the skin friction coefficient is kept at a low, constant level. Although the Reynolds stress distribution across the layer is entirely different from the flow at zero pressure gradient, the ratios between the different turbulent stress components were found to be similar, showing that the mechanism for distributing the turbulent energy between the different components remains unaffected by the mean flow pressure gradient. Close to the surface the gradient of the mixing length was found to increase from 0.41 to 0.78. This is almost twice as high as for the zero pressure gradient case. The multi-point measurements indicated strong effects of the pressure gradient on the turbulent structure of the boundary layer. The average inclination from the wall in the (x, y) plane was found to be much more constant (about 20 degrees) through the layer than in the zero pressure gradient case. The length scales associated with the two-point correlations of the velocity fluctuations increased much faster with respect to the distance from the wall. In the bulk part of the layer the length scales were comparable to the length scales found in the zero pressure gradient layer, except for the streamwise length scale of the two-point correlation which was approximately half the length. Similarity in the triple correlation was also found to be good. The correlations show that there is a considerable diffusion of turbulent energy from the central part of the boundary layer towards the wall. The diffusion mechanism is caused by a second peak in the turbulence production, located at y/{delta} to be about 0.45. This production was for the present case almost as strong as the production found near the wall.}

place = {Norway}

year = {1994}

month = {Dec}

}