Very-large-scale coherent structures in the wall pressure field beneath a supersonic turbulent boundary layer

2013 ◽  
Vol 25 (9) ◽  
pp. 095104 ◽  
Author(s):  
Steven J. Beresh ◽  
John F. Henfling ◽  
Russell W. Spillers ◽  
Brian O. M. Pruett
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Coherent Structures ◽  
Large Scale ◽  
Pressure Field ◽  
Wall Pressure

Decay of fluctuating wall-pressure field of Mach 5 turbulent boundary layer

AIAA Journal ◽  
1999 ◽  
Vol 37 ◽  
pp. 1088-1096
Author(s):  
O. H. Unalmis ◽  
D. S. Dolling
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Pressure Field ◽  
Wall Pressure

Fluid-Loaded Vibration due to a Non-Homogeneous Turbulent Boundary Layer

2014 ◽  
Author(s):  
Jason R. Tomko ◽  
Scott C. Morris
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Pressure Field ◽  
Wall Pressure ◽  
Mode Shapes ◽  
Phase Identification ◽  
Structural Acoustics ◽  
Spatially Homogeneous ◽  
Layer Flow ◽  
Loaded Structure

Flow-induced structural acoustics involves the study of the vibration of a structure induced by a fluid flow as well as the resulting sound generated and radiated by the motion of the structure. A thin rectangular, structure, non-fluid-loaded was excited by turbulent boundary layer flow. A method called magnitude-phase identification (MPI) is derived to measure modal information from a structure using only two-point measurements. Using MPI, the mode shapes and the auto-spectral density of vibration of each mode was measured and found to agree well with the theoretical values. When the non-fluid-loaded structure was excited with a spatially non-homogeneous wall pressure field or fluid-loaded structure was excited with a spatially homogeneous wall pressure field, the measured mode shapes were found to be the same as those predicted by theory. When a fluid-loaded structure was excited with a spatially non-homogeneous wall pressure field, the mode shapes were found to change. This suggests that standard modal analysis may not be sufficient to predict the vibration of fluid-loaded structures, as such theory assumes that the mode shapes of the structure are independent of the method by which the structure is excited.

Decay of Fluctuating Wall-Pressure Field of Mach 5 Turbulent Boundary Layer

AIAA Journal ◽  
10.2514/2.837 ◽  
1999 ◽  
Vol 37 (9) ◽  
pp. 1088-1096 ◽  
Author(s):  
O. H. Unalmis ◽  
D. S. Dolling
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Pressure Field ◽  
Wall Pressure

Space–time pressure–velocity correlations in a turbulent boundary layer

2015 ◽  
Vol 771 ◽  
pp. 624-675 ◽  
Author(s):  
Yoshitsugu Naka ◽  
Michel Stanislas ◽  
Jean-Marc Foucaut ◽  
Sebastien Coudert ◽  
Jean-Philippe Laval ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Coherent Structures ◽  
Boundary Layer Thickness ◽  
Large Scale ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Sweeping Motion ◽  
Spatio Temporal ◽  
Scale Motion

The spatio-temporal pressure–velocity correlation in a turbulent boundary layer is investigated so as to understand the link between pressure fluctuations and turbulent coherent structures. A new experimental set-up is developed to measure the pressure fluctuations at the wall and in the field and, simultaneously, the velocity field by stereoscopic particle image velocimetry. The present measurement area covers the whole boundary layer thickness, and the spatial resolution of the measurement is good enough to assess the representative length scales of the flow. The Reynolds number effect is quantified from the data at $\mathit{Re}_{{\it\theta}}=7300$, 10 000, 18 000. The spatio-temporal three-dimensional structures of the pressure–velocity correlations, $\boldsymbol{R}_{pu}$, $\boldsymbol{R}_{pv}$ and $\boldsymbol{R}_{pw}$, are evaluated. The wall pressure fluctuations are closely coupled with coherent structures which occupy a large region of the boundary layer in the wall-normal and spanwise directions and up to $10{\it\delta}/U_{e}$ in time, where ${\it\delta}$ and $U_{e}$ denote the boundary layer thickness and the free stream velocity. Reynolds number effects are mainly observed on the size and intensity of the pressure–velocity correlations. Conditioning the correlations on the pressure signal sign shows different types of flow phenomena linked to the positive and negative pressure events. For the wall pressure, positive pressure fluctuations appear to be correlated with the leading edge of a large sweeping motion of splatting type followed by a large ejection. The negative pressure fluctuations are linked to a localized ejection upstream, followed by a large sweeping motion downstream. For the pressure fluctuations in the field, in addition to the structures observed with the wall pressure, the pressure–velocity correlations exhibit a significant correlation in a region very extended in time. Such long structures appear to be independent of the one observed at the wall and to grow significantly in time with the Reynolds number when scaling with external variables. When conditioned by the pressure sign, clear ejection and sweeping motions are observed with associated streamwise vortical structures at a scale of the order of $0.2{\it\delta}$. These structures can be linked to the large-scale motion and very-large-scale motion previously observed by different authors and seem to organize in a scheme analogous to the near-wall cycle, but at a much larger scale.

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