Numerical investigations of aeroacoustic aspects of clarinet-like instruments
Bibliographic record
Abstract
This thesis presents numerical investigations of the aeroacoustic aspects of clarinetlike instruments.A customized simulation system based on the two-dimensional lattice Boltzmann method is developed to address acoustic problems involving complex boundary conditions carrying a low Mach number mean flow.The simulation is accelerated by means of GPU parallel computing.The accuracy and stability of the modeling system are substantiated by benchmark acoustic problems involving static boundaries, which include the acoustic transmission and radiation characteristics of axisymmetric waveguides terminated by different geometries, as well as the aeroacoustic behavior of whistles with complicated curved geometries.The effect of non-zero subsonic mean flow is investigated.The numerical results agree well with those provided by available theories and experimental data.The accuracy of the 32-bit representation of floating-point numbers in the GPU-accelerated computations is also verified.Aspects of fluid-acoustic-structure interaction of a clarinet that comprises a dynamic mouthpiece-reed structure and an acoustic resonator are investigated in both a quasistationary regime and a dynamic regime.The effect of different lay geometries is investigated as well.For the case of a fixed reed, the vena contracta factor varies very little over approximately 80% of the duration, which is in general agreement with the current theory.For the case of a slowly moving reed, hysteresis is found in the numerical flow due to the inertia of the fluid volume.The vena contracta factor is greater than unity in the region of high pressure differences, which is in contrast with the theoretical assumption and is due to the non-uniform height across the reed channel.In simulations carried out for a dynamic regime with acoustic feedback, the phenomenon of flow separation / reattachment in a reed channel, as well as the vena contracta factors, are significantly different from the theoretical expectations.The acoustic perturbation of the pressure and velocity fields in a mouthpiece chamber and reed channel are visualized with high resolution.The effect of different lay geometries is observable in many aspects, including the earlier acceleration of volume flow in the short channel and the extra energy dissipation in the long channel with a ditch at the end.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".