Scaling of wall-pressure--velocity correlations in high Reynolds number turbulent pipe flow
Fuente:
arXiv
Enregistré dans:
| Auteurs principaux: | , , , , |
|---|---|
| Format: | Preprint |
| Publié: |
2025
|
| Sujets: | |
| Accès en ligne: | |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1866917892452253696 |
|---|---|
| author | Dacome, Giulio Lazzarini, Lorenzo Talamelli, Alessandro Bellani, Gabriele Baars, Woutijn J. |
| author_facet | Dacome, Giulio Lazzarini, Lorenzo Talamelli, Alessandro Bellani, Gabriele Baars, Woutijn J. |
| contents | An experimental study was conducted in the CICLoPE long-pipe facility to investigate the correlation between wall-pressure and turbulent velocity fluctuations in the logarithmic region, at high friction Reynolds numbers ($4\,794 \lesssim Re_τ\lesssim 47\,015$). Hereby we explore the scalability of employing wall-pressure to effectively estimate off-the-wall velocity states (e.g., to be of use in real-time control of wall-turbulence). Coherence spectra for wall-pressure and streamwise (or wall-normal) velocity fluctuations collapse when plotted against $λ_x/y$ and thus reveals a Reynolds-number-independent scaling with distance-from-the-wall. When the squared wall-pressure fluctuations are considered instead of the linear wall-pressure term, the coherence spectra for the wall-pressure--squared and velocity are higher in amplitude at wavelengths corresponding to large-scale streamwise velocity fluctuations (e.g., at $λ_x/y = 60$ the coherence value increases from roughly 0.1 up to 0.3). This higher coherence typifies a modulation effect, because low-frequency content is introduced when squaring the wall-pressure time series. Finally, quadratic stochastic estimation is employed to estimate turbulent velocity fluctuations from the wall-pressure time series only. For each $Re_τ$ investigated, the estimated time series and a true temporal measurement of velocity inside the turbulent pipe flow, yield a normalized correlation coefficient of $ρ\approx 0.6$ for all cases. This suggests that wall-pressure sensing can be employed for meaningful estimation of off-the-wall velocity fluctuations, and thus for real-time control of energetic turbulent velocity fluctuations at high $Re_τ$ applications. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_08018 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Scaling of wall-pressure--velocity correlations in high Reynolds number turbulent pipe flow Dacome, Giulio Lazzarini, Lorenzo Talamelli, Alessandro Bellani, Gabriele Baars, Woutijn J. Fluid Dynamics An experimental study was conducted in the CICLoPE long-pipe facility to investigate the correlation between wall-pressure and turbulent velocity fluctuations in the logarithmic region, at high friction Reynolds numbers ($4\,794 \lesssim Re_τ\lesssim 47\,015$). Hereby we explore the scalability of employing wall-pressure to effectively estimate off-the-wall velocity states (e.g., to be of use in real-time control of wall-turbulence). Coherence spectra for wall-pressure and streamwise (or wall-normal) velocity fluctuations collapse when plotted against $λ_x/y$ and thus reveals a Reynolds-number-independent scaling with distance-from-the-wall. When the squared wall-pressure fluctuations are considered instead of the linear wall-pressure term, the coherence spectra for the wall-pressure--squared and velocity are higher in amplitude at wavelengths corresponding to large-scale streamwise velocity fluctuations (e.g., at $λ_x/y = 60$ the coherence value increases from roughly 0.1 up to 0.3). This higher coherence typifies a modulation effect, because low-frequency content is introduced when squaring the wall-pressure time series. Finally, quadratic stochastic estimation is employed to estimate turbulent velocity fluctuations from the wall-pressure time series only. For each $Re_τ$ investigated, the estimated time series and a true temporal measurement of velocity inside the turbulent pipe flow, yield a normalized correlation coefficient of $ρ\approx 0.6$ for all cases. This suggests that wall-pressure sensing can be employed for meaningful estimation of off-the-wall velocity fluctuations, and thus for real-time control of energetic turbulent velocity fluctuations at high $Re_τ$ applications. |
| title | Scaling of wall-pressure--velocity correlations in high Reynolds number turbulent pipe flow |
| topic | Fluid Dynamics |
| url | https://arxiv.org/abs/2501.08018 |