How Does This App Blow Out Candles?

demonstration, basic explanation and some parameter variations

https://youtu.be/tX6XSs2T5Go?feature=shared

Using Sound as a Fire Extinguisher

demonstration in a larger scale and some physical insights
(Don't do this at home or without adults!)

https://youtu.be/ZvnCQg4w4o8?feature=shared

Acoustic flame extinction by the sound wave or speaker-induced wind?

Experimental work using a candle flame which is tested in two kinds of sound fields, one developing freely and the other guided by a cylindrical tube.

https://doi.org/10.1016/j.firesaf.2021.103479

Analysis of Flame Extinguishment and Height in Low Frequency Acoustically Excited Methane Jet Diffusion Flame

Gives first experimental insights into the experiment and shows first important parameters. A sophisticated setup is used, which in any case gives a good approach to build a very useful experimental setup.
Theoretically, however, the paper is rather weak and gives only a rough qualitative explanation.
Furthermore, although the paper mentions micro gravity in the abstract, it is not used in the experimental setup. Gravity would also not be too relevant to this problem.

https://link.springer.com/article/10.1007/s12217-017-9590-5

Application of acoustic oscillations in quenching of gas burner flame

This paper concerns the flame extinguishing with the use of acoustic waves. A small laboratory stand allowing to generate acoustic waves in the horizontal direction was used for that purpose. The speaker extinction power and the acoustic extinction pressure were selected to quantify the process. Varying frequencies (30–50 Hz) burner powers (3.45-11.72 kW) and distances between the acoustic source and the flame (0.02–0.06 m) were investigated.

https://www.sciencedirect.com/science/article/pii/S0010218018302013

Classification of flame extinction based on acoustic oscillations using artificial intelligence methods

Within the scope of this study, a sound wave flame extinction system was developed in order to extinguish the flames at an early stage of the fire. The data used in the study were obtained as a result of experiments conducted with the developed system. The created dataset consists of data obtained from 17,442 experiments. It is aimed to classify the fuel type, flame size, decibel, frequency, airflow and distance features, and the extinction-non-extinction status of the flame through rule-based machine learning methods.

https://www.sciencedirect.com/science/article/pii/S2214157X21007243

Fluctuation and extinction of laminar diffusion flame induced by external acoustic wave and source

This work applies a loudspeaker to extinguish a laminar diffusion propane flame of 5–25 mm high, where the local sound frequency is 50–70 Hz and sound pressure is 0.8–3.2 Pa (92.0–104.1 dB). Results reveal a constant flame pulsating displacement at the extinction limit, independent of the sound environment used. Such a flame pulsating displacement is found to be caused by the motion of the speaker membrane and its induced wind, which could be two orders of magnitude larger than the displacement of the air that transmits acoustic wave.

https://www.nature.com/articles/s41598-021-93648-0