Bulletin of the American Physical Society
72nd Annual Meeting of the APS Division of Fluid Dynamics
Volume 64, Number 13
Saturday–Tuesday, November 23–26, 2019; Seattle, Washington
Session G11: Turbulent Boundary Layers: High Re Effects |
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Chair: Alexander Smits, Princeton University Room: 3B |
Sunday, November 24, 2019 3:48PM - 4:01PM |
G11.00001: Molecular Tagging Velocimetry Study of High Reynolds Number Turbulent Pipe Flow in Cryogenic Helium Hamid Sanavandi, Shiran Bao, Yang Zhang, Wei Guo, Louis Cattafesta Cryogenic helium-4 has considerable potential in fluids research due to a very small kinematic viscosity, suitable to generate and study high Reynolds number turbulent flow within a compact laboratory apparatus. However, studying the flow in helium-4 has been challenging largely due to the lack of effective visualization and velocimetry techniques. Here we have assembled a novel instrumentation including a 335 cm long horizontal cryogenic helium channel with a square 4cm$^{\mathrm{2}}$ cross-section. This allows us to generate fully-developed turbulent pipe flows with Reynolds numbers above 10$^{\mathrm{6}}$. We implement a unique molecular tagging velocimetry (MTV) method based on tracking two parallel thin He$_{\mathrm{2}}^{\mathrm{\ast }}$ molecular tracer lines created perpendicular to the pipe wall with an adjustable distance via femtosecond laser-field ionization. By observing the displacement and distortion of the tracer lines, we can measure the near-wall mean velocity profile, velocity fluctuation profile, as well as both the transverse and longitudinal spatial velocity correlations We also report the pressure drop data acquired from the experimental channel using a differential pressure transducer, then the friction factor coefficient can be determined. [Preview Abstract] |
Sunday, November 24, 2019 4:01PM - 4:14PM |
G11.00002: Experimental study for turbulent pipe flow at high Reynolds number using LDV - Turbulent intensity profile and influence of measurement volume Noriyuki Furuichi, Eisuke Kusano, Yuki Wada, Yoshiyuki Tsuji We have done new experiments for turbulent pipe flow at high Reynolds number, up to Re\textunderscore tau$=$300,000 using Hi-Reff. In the experiments, the friction factor was measured by the pressure drop along the pipe and the velocity was measured using LDV. In this paper, authors make a focus on the turbulent intensity profile in the pipe flow at high Reynolds number. As one of issues of the measurement, the spatial resolution of the measurement is very sensitive for the turbulent intensity for any measurement methods. With increasing Reynolds number, the relative measurement volume of LDV increases. This issue has been discussed for the hot-wire measurement, however still not done for the LDV. In this paper, the influence of the measurement volume of LDV at the wall bounded flow is studied as first. The measurement volume of LDV is controlled by the changing the insertion angle of the laser. Based on the relation between the normalized spatial resolution L$+$ and Reynolds number, the criteria for the measurement at high Reynolds number is clarified. Secondary, the trend with Reynolds number of turbulent intensity profile for streamwise and wall-normal component are reported. Those data are compared with DNS data. [Preview Abstract] |
Sunday, November 24, 2019 4:14PM - 4:27PM |
G11.00003: Numerical investigation on very-large-scale motions and the amplitude modulation in the atmospheric boundary layer at very high Reynolds number Hehe Ren, Shujin Laima, Hui Li Wall Model Large Eddy Simulations (WMLES) were carried out to investigate the spatial features of very-large-scale motions (VLSMs) in the atmospheric boundary layer flow under different surface roughness at very high Reynolds number, $o $(10$^{\mathrm{6}}$\textasciitilde 10$^{\mathrm{7}})$. The simulation results display good agreement with field observation and experimental data. By pre-multiplied spectral analysis, the VLSMs reduces or even disappears with increasing roughness, which supports the “Bottom-up” mechanism indirectly. From the perspective of spatial correlation of flow field, the structural characteristics of VLSMs under various roughness were shown well with observation data. Furthermore, the amplitude modulation (AM) that exerted by the outer layer large-scale motions on the near-wall small-scale motions was discussed. It was found the negative maximum correlation decreases with increasing Reynolds number. And there is an approximate collapse of correlation over different magnitude in Reynolds number when scaled with outer variables. Finally, the physical meaning of the reversal in sign of correlation corresponds to the cross-point of small-scale turbulent intensity and the local peak of energy distribution was found. [Preview Abstract] |
Sunday, November 24, 2019 4:27PM - 4:40PM |
G11.00004: Inertial-layer Mean Velocity Profiles for extreme Reynolds number flows Fabio Ramos, Hamidreza Anbarlooei, Daniel Cruz For fully developed statistically stationary channel and pipe flows with smooth walls, any averaged quantity of the flow at a distance y from the wall can be specified by the control parameters $\rho$, $\mu$, $u_{\tau}$ and $y$ itself. By the Pi theorem, there exist only three non-dimensional groups that can be formed from the combination of $\langle u\rangle(y)$ or $\frac{d\langle u\rangle}{dy}(y)$, and those quantities. In an earlier work, by observing that center of the log-law scales as the geometric mean $\sqrt{\delta \delta_{\nu}}$, we have proposed an attached eddy framework, which results on a new friction factor formula for extreme Reynolds number, namely $f\sim \frac{1}{Re^{2/13}}$. In this work, by assuming incomplete self-similarity, we show that the new friction factor is compatible with a new MVP formula, namely $\langle u\rangle(y)=u_{\tau}\Phi(\frac{y}{\delta},\frac{y}{\sqrt{\delta \delta_{\nu}}}),$ which in wall units result in the new expression $ u^+=A (y^+)^{1/12}+\frac{B}{Re_{\tau}^{1/12}} (y^+)^{1/6} .$ This formula, with only two free parameters, results in a very good fit for the MVP data obtained from Princeton superpipe experiments, for a large range of extreme Reynolds number, $Re>10^7$, and for a large radial extension above the log-law range. [Preview Abstract] |
Sunday, November 24, 2019 4:40PM - 4:53PM |
G11.00005: Invariant PDF profile in the log-region of high-Re-number turbulent boundary layer Yoshiyuki Tsuji, Atsuhi Ido, Michio Nishioka The probability density function (pdf) of a streamwise velocity component is studied in zero-pressure gradient boundary layers. From analyzing the data up to $R_\theta \sim 80000$, it is found that pdfs have self-similar profiles in the log-law region of mean velocity. Pdf profiles asymptote to the universal shape very close to the Gaussian, but are positively skewed at the core region, indicating smaller values in the tail parts. In the log-law region of turbulence intensity, pdf is positively skewed slightly. These characteristics are summarized depending on the Reynolds number. [Preview Abstract] |
Sunday, November 24, 2019 4:53PM - 5:06PM |
G11.00006: The energy budget at the outer peak of $\overline{u^2}$ in turbulent pipe flow. Jonathan Morrison, Jose Fernandez Vicente We use the NSTAP data from the Princeton superpipe (Vallikivi PhD thesis 2014) to examine the spatial \& spectral energy fluxes close to the outer peak in $\overline {u^2}$ in the range of Reynolds numbers, $2.1 \times 10^6 \le Re_D \le 6.0 \times 10^6$, for which the ratio of hot-wire length to Kolmogorov length scale is $ l/\eta \approx 10$. Previous results (Hultmark {\it et al.} PRL, {\bf 108}, 2012) suggest that the outer peak emerges at $Re_D \approx 1.1 \times 10^6$, its position exhibiting a locus $y_m^+=0.23(Re^+)^{0.67}$. We note that this is close to the position of the well-known ``mesolayer'', which we have also described as the intermediate layer with scaling ($y_m^+ \propto \sqrt{Re_\tau}, u_m$), where $u_m$ is the rms velocity at $y=y_m$ (Diwan \& Morrison, TSFP11 -- see also the presentation in the session, ``Turbulent Boundary Layers''). It is straightforward to show that the locus of $u_m$ is close to that for the production, $P_m(\overline{u^2})$, where the local-equilibrium approximation approximately holds. Therefore, spectral dynamics are most Kolmogorov-like because spatial transport is minimal. We examine the inertial scaling of the axial velocity spectra and low-order structure functions to explain the importance of intermediate scaling. [Preview Abstract] |
Sunday, November 24, 2019 5:06PM - 5:19PM |
G11.00007: Thermal transport in hypersonic turbulent boundary layers at high-Reynolds numbers Jean Santiago, Nathan Tichenor, Guillermo Araya The evolution of thermal spatially-developing turbulent boundary layers (SDTBL) is studied experimentally and numerically at the hypersonic regime. Experiments were performed in a high-speed blow-down wind tunnel facility located in the National Aerothermochemistry and Hypersonics Laboratory (NAL) at Texas A\&M University (TAMU) over a zero-pressure gradient (ZPG) adiabatic flat plate at a Mach number of 4.9 and a Reynolds number of 9,000 based on freestream density, momentum thickness, freestream velocity and wall viscosity. Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) of SDTBL at low and high Reynolds numbers are designed in harmony with experiments. Turbulent inflow information is generated via the dynamic rescaling-recycling approach (J. Fluid Mech., 670, pp. 581-605, 2011), which is extended to compressible flows. DNS and LES results of the velocity field are validated by particle image velocimetry (PIV) experiments. Focus is given to the assessment of Reynolds number on the thermal fluctuations and turbulent heat fluxes, as well as their vertical transport. This presentation will emphasize the calibration effort of the numerical model in order to capture the measured flow structure. [Preview Abstract] |
Sunday, November 24, 2019 5:19PM - 5:32PM |
G11.00008: Inter-scale modulation in pipe flows at high $Re_{\tau}$ Xiaobo Zheng, Ye Li, Gabriele Bellani, Lucia Mascotelli, Alessandro Talamelli Hot-wire measurements of streamwise velocity are conducted in the large-scale pipe-flow facility CICLoPE in the friction Reynolds number range $7800 |
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