Wavenumber-frequency analysis of turbulent wall pressure fluctuations over a wide Reynolds number range of Turbulent Pipe Flows

2011 ◽  
Author(s):  
William Keith ◽  
Alia Foley ◽  
Kimberly Cipolla
Keyword(s):  
Reynolds Number ◽  
Frequency Analysis ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Number Range ◽  
Pipe Flows ◽  
Wall Pressure Fluctuations ◽  
Reynolds Number Range ◽  
Turbulent Wall

The Wavenumber-Phase Velocity Representation for the Turbulent Wall-Pressure Spectrum

1994 ◽  
Vol 116 (3) ◽  
pp. 477-483 ◽  
Author(s):  
Ronald L. Panton ◽  
Gilles Robert
Keyword(s):  
Scaling Laws ◽  
Flow Direction ◽  
Pressure Fluctuations ◽  
Phase Speed ◽  
Universal Function ◽  
Wall Pressure ◽  
Large Reynolds Number ◽  
Number Range ◽  
Wall Pressure Fluctuations ◽  
Turbulent Wall

Wall-pressure fluctuations can be represented by a spectrum level that is a function of flow-direction wavenumber and frequnecy, Φ (k1, ω). In the theory developed herein the frequency is replaced by a phase speed; ω = ck1. At low wavenumbers the spectrum is a universal function if nondimensionalized by the friction velocity u* and the boundary layer thickness δ, while at high wavenumbers another universal function holds if nondimensionalized by u* and viscosity ν. The theory predicts that at moderate wavenumbers the spectrum must be of the form Φ+ (k+1, ω+ = c+ k+1) = k+1 − 2 P+ (Δc+) where P+ (Δc+) is a universal function. Here Δc+ is the difference between the phase speed and the speed for which the maximum of Φ+ occurs. Similar laws exist in outer variables. New measurements of the wall-pressure are given for a large Reynolds number range; 45,000 < Re = Uoδ/ν < 113,000. The scaling laws described above were tested with the experimental results and found to be valid. An experimentally determined curve for P+ (Δc+) is given.

Pressure and velocity measurements of an incompressible moderate Reynolds number jet interacting with a tangential flat plate

2015 ◽  
Vol 770 ◽  
pp. 247-272 ◽  
Author(s):  
A. Di Marco ◽  
M. Mancinelli ◽  
R. Camussi
Keyword(s):  
Reynolds Number ◽  
Flat Plate ◽  
Scaling Laws ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Theoretical Modelling ◽  
Wall Pressure Fluctuations ◽  
Moderate Reynolds Number ◽  
The Mean ◽  
Pressure And Velocity Measurements

The statistical properties of wall pressure fluctuations generated on a rigid flat plate by a tangential incompressible single stream jet are investigated experimentally. The study is carried out at moderate Reynolds number and for different distances between the nozzle axis and the flat plate. The overall aerodynamic behaviour is described through hot wire anemometer measurements, providing the effect of the plate on the mean and fluctuating velocity. The pressure field acting on the flat plate was measured by cavity-mounted microphones, providing point-wise pressure signals in the stream-wise and span-wise directions. Statistics of the wall pressure fluctuations are determined in terms of time-domain and Fourier-domain quantities and a parametric analysis is conducted in terms of the main geometrical length scales. Possible scaling laws of auto-spectra and coherence functions are presented and implications for theoretical modelling are discussed.

Spectral and Temporal Characteristics of Post-Stenotic Turbulent Wall Pressure Fluctuations

1979 ◽  
Vol 101 (2) ◽  
pp. 89-95 ◽  
Author(s):  
W. H. Pitts ◽  
C. F. Dewey
Keyword(s):  
Steady Flow ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Experimental Uncertainty ◽  
Flow Parameters ◽  
Wall Pressure Fluctuations ◽  
Power Spectral ◽  
Fluctuation Amplitude ◽  
Arterial Constriction ◽  
Turbulent Wall

The power spectral density of turbulent wall pressure fluctuations was measured in a tube downstream of a model arterial constriction. The flow parameters were varied from steady flow to conditions simulating human arterial pulsatile flow. Within the experimental uncertainty (±10 percent in characteristic turbulent frequency, fo, and ±25 percent in absolute rms pressure fluctuation amplitude), turbulent flow at the peak of systole produces wall pressure fluctuations identical to those of a steady flow at the same Reynolds number.

Reynolds-number dependence of wall-pressure fluctuations in a pressure-induced turbulent separation bubble

2017 ◽  
Vol 833 ◽  
pp. 563-598 ◽  
Author(s):  
Hiroyuki Abe
Keyword(s):  
Reynolds Number ◽  
Pressure Gradient ◽  
Large Scale ◽  
Separation Bubble ◽  
Pressure Fluctuations ◽  
Local Maximum ◽  
Wall Pressure ◽  
Mean Flow ◽  
Frequency Spectra ◽  
Wall Pressure Fluctuations

Direct numerical simulations are used to examine the behaviour of wall-pressure fluctuations $p_{w}$ in a flat-plate turbulent boundary layer with large adverse and favourable pressure gradients, involving separation and reattachment. The Reynolds number $Re_{\unicode[STIX]{x1D703}}$ based on momentum thickness is equal to 300, 600 and 900. Particular attention is given to effects of Reynolds number on root-mean-square (r.m.s.) values, frequency/power spectra and instantaneous fields. The possible scaling laws are also examined as compared with the existing direct numerical simulation and experimental data. The r.m.s. value of $p_{w}$ normalized by the local maximum Reynolds shear stress $-\unicode[STIX]{x1D70C}\overline{uv}_{max}$ (Simpson et al. J. Fluid Mech. vol. 177, 1987, pp. 167–186; Na & Moin J. Fluid Mech. vol. 377, 1998b, pp. 347–373) leads to near plateau (i.e. $p_{w\,rms}/-\unicode[STIX]{x1D70C}\overline{uv}_{max}=2.5\sim 3$) in the adverse pressure gradient and separated regions in which the frequency spectra exhibit good collapse at low frequencies. The magnitude of $p_{w\,rms}/-\unicode[STIX]{x1D70C}\overline{uv}_{max}$ is however reduced down to 1.8 near reattachment where good collapse is also obtained with normalization by the local maximum wall-normal Reynolds stress $\unicode[STIX]{x1D70C}\overline{vv}_{max}$. Near reattachment, $p_{w\,rms}/-\unicode[STIX]{x1D70C}\overline{vv}_{max}=1.2$ is attained unambiguously independently of the Reynolds number and pressure gradient. The present magnitude (1.2) is smaller than (1.35) obtained for step-induced separation by Ji & Wang (J. Fluid Mech. vol. 712, 2012, pp. 471–504). The reason for this difference is intrinsically associated with convective nature of a pressure-induced separation bubble near reattachment where the magnitude of $p_{w\,rms}$ depends essentially on the favourable pressure gradient. The resulting mean flow acceleration leads to delay of the r.m.s. peak after reattachment. Attention is also given to structures of $p_{w}$. It is shown that large-scale spanwise rollers of low pressure fluctuations are formed above the bubble, whilst changing to large-scale streamwise elongated structures after reattachment. These large-scale structures become more prominent with increasing $Re_{\unicode[STIX]{x1D703}}$ and affect $p_{w}$ significantly.

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