Vortex-flow mechanism of cavity tone with acoustic resonance

To clarify the effects of freestream turbulence on cavity tones, flow and acoustic fields were directly predicted for cavity flows with various intensities of freestream turbulence. The freestream Mach number was 0.09 and the Reynolds number based on the cavity length was 4.0 × 104. The depth-to-length ratio of the cavity,D/L, was 0.5 and 2.5, where the acoustic resonance of a depth-mode occurs forD/L= 2.5. The incoming boundary layer was laminar. The results for the intensity of freestream turbulence of Tu = 2.3% revealed that the reduced level of cavity tones in a cavity flow with acoustic resonance(D/L=2.5)was greater than that without acoustic resonance(D/L=0.5). To clarify the reason for this, the sound source based on Lighthill’s acoustic analogy was computed, and the contributions of the intensity and spanwise coherence of the sound source to the reduction of the cavity tone were estimated. As a result, the effects of the reduction of spanwise coherence on the cavity tone were greater in the cavity flow with acoustic resonance than in that without resonance, while the effects of the intensity were comparable for both flows.

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Investigation on Flow Mechanism of Secondary Erosion

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations ◽

10.1115/91-gt-383 ◽

1991 ◽

Cited By ~ 1

Author(s):

Zhiguang Ling ◽

Yiqing Yuan

Keyword(s):

Particle Deposition ◽

Gas Flow ◽

Vortex Flow ◽

Flow Model ◽

Research Direction ◽

Vortex Chamber ◽

Flow Mechanism ◽

Suggested Model ◽

New Research ◽

Aggregation Tendency

Secondary erosion caused by particulate flow is a new research direction. On the basis of numerical analysis of the trajectory of particle motion in rotating gas flow, its equilibrium condition and causes of aggregation, a physical flow model of secondary erosion is suggested. By this model the mechanism of secondary erosion caused by particulate gas flow could be primarily explained. The vortex chamber experiment verifies the particle aggregation tendency in vortex flow and the experiment of particle deposition in bending tube proves in certain extent the correctness of the suggested model.

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Assessment of Tongue Position and Laryngeal Height in Two Professional Voice Populations

Journal of Speech Language and Hearing Research ◽

10.1044/2019_jslhr-19-00164 ◽

2020 ◽

Vol 63 (1) ◽

pp. 109-124

Author(s):

Carly Jo Hosbach-Cannon ◽

Soren Y. Lowell ◽

Raymond H. Colton ◽

Richard T. Kelley ◽

Xue Bao

Keyword(s):

Vocal Fold ◽

Vocal Tract ◽

Current Knowledge ◽

Acoustic Resonance ◽

Contact Dynamics ◽

Voice Disorder ◽

Music Program ◽

Tongue Position ◽

Singer Groups ◽

Professional Voice

Purpose To advance our current knowledge of singer physiology by using ultrasonography in combination with acoustic measures to compare physiological differences between musical theater (MT) and opera (OP) singers under controlled phonation conditions. Primary objectives addressed in this study were (a) to determine if differences in hyolaryngeal and vocal fold contact dynamics occur between two professional voice populations (MT and OP) during singing tasks and (b) to determine if differences occur between MT and OP singers in oral configuration and associated acoustic resonance during singing tasks. Method Twenty-one singers (10 MT and 11 OP) were included. All participants were currently enrolled in a music program. Experimental procedures consisted of sustained phonation on the vowels /i/ and /ɑ/ during both a low-pitch task and a high-pitch task. Measures of hyolaryngeal elevation, tongue height, and tongue advancement were assessed using ultrasonography. Vocal fold contact dynamics were measured using electroglottography. Simultaneous acoustic recordings were obtained during all ultrasonography procedures for analysis of the first two formant frequencies. Results Significant oral configuration differences, reflected by measures of tongue height and tongue advancement, were seen between groups. Measures of acoustic resonance also showed significant differences between groups during specific tasks. Both singer groups significantly raised their hyoid position when singing high-pitched vowels, but hyoid elevation was not statistically different between groups. Likewise, vocal fold contact dynamics did not significantly differentiate the two singer groups. Conclusions These findings suggest that, under controlled phonation conditions, MT singers alter their oral configuration and achieve differing resultant formants as compared with OP singers. Because singers are at a high risk of developing a voice disorder, understanding how these two groups of singers adjust their vocal tract configuration during their specific singing genre may help to identify risky vocal behavior and provide a basis for prevention of voice disorders.

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ANALISIS VARIASI JUMLAH SUDU TURBIN BERPENAMPANG PELAT DATAR PADA TURBIN AIR ALIRAN VORTEX DENGAN TIPE SALURAN MASUK INVOLUTE

JURNAL ILMIAH TEKNIK MESIN ◽

10.33558/jitm.v7i2.1917 ◽

2020 ◽

Vol 7 (2) ◽

pp. 72-78

Author(s):

Adnan Al Farisi ◽

Yopi Handoyo ◽

Taufiqur Rokhman

Keyword(s):

Power Plant ◽

Alternative Energy ◽

Vortex Flow ◽

Experimental Methods ◽

Turbine Efficiency ◽

A Value ◽

Current Voltage ◽

Materials Research ◽

The One ◽

Flow Vortex

The One of alternative energy that is environmentally friendly is by untilize water energy and turn it into a Microhydro power plant. Microhydro power plant usually made from utilize the waterfall with the head fell. While utilization for streams with a head small drop is not optimal yet. This is a reference to doing research on harnessing the flow of a river that has a value of head low between 0.7 m – 1.4 m with turning it into a Vortex flow (vortex). The purpose of this research is to know the effect variation number of blade on power and efficiency in the vortex turbine. This research uses experimental methods to find current, voltage, torque and rpm using a reading instrument. The materials research vortex turbine used 6 blade, 8 blade and 10 blade with flat plate. The result showed the highest efficiency is 29,93 % with produce turbine power is 19,58 W, generated on turbine with variation 10 blade with load 3,315 kg and the capacity of water 10,14 l/s. Followed with an efficiency 24,17% and produce turbine power is 15,81 W, generated on turbine with the variation 8 blade with load 3,315 kg and the capacity of water is 10,14 l/s. The the lowest turbine efficiency 22,32% with produce tuebine power 14,60 W, generated on turbine with the variation 6 blade with load 3,315 kg, the capacity of water is 10,14 l/s.

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