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The propagation of sound waves through a blade row is investigated numerically. A wave splitting method in a two-dimensional duct with arbitrary mean flow is presented, based on which pressure amplitude of different wave mode can be extracted at an axial plane. The propagation of sound wave through a flat plate blade row has been simulated by solving the unsteady Reynolds average Navier-Stokes equations (URANS). The transmission and reflection coefficients obtained by Computational Fluid Dynamics (CFD) are compared with semi-analytical results. It indicates that the low order URANS scheme will cause large errors if the sound pressure level is lower than -100 dB (with as reference pressure the product of density, main flow velocity, and speed of sound). The CFD code has sufficient precision when solving the interaction of sound wave and blade row providing the boundary reflections have no substantial influence. Finally, the effects of flow Mach number, blade thickness, and blade turning angle on sound propagation are studied.
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http://dx.doi.org/10.1121/1.4740499 | DOI Listing |
PhytoKeys
May 2025
Herbario de la Universidad de Panamá, Facultad de Ciencias Naturales, Exactas y Tecnología, Campus Octavio Méndez Pereira, Panama, Panama Herbario de la Universidad de Panamá, Facultad de Ciencias Naturales, Exactas y Tecnología Panama Panama.
is described as a new species of BegoniasectionLepsia from Cerro Chucantí, Darién Province, in eastern Panama. A study of the literature and herbarium specimens, as well as fieldwork, suggests that the new taxon is distinguished from other species in the section by the combination of the following characters: uniform nodes, stipules persistent, 3.3-6 × 0.
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June 2024
Aerodynamic and Compressible Turbomachine Research Laboratory, School of Mechanical Engineering, Iran University of Science and Technology (IUST), NarmakTehran, 16846-13114, Iran.
This paper presents results of aerodynamic enhancement of axial compressors utilizing optimum natural aspiration through a circumferential slot made within the casing wall upstream the rotor blades row. The method of investigation is based on numerical simulation of flow field. Geometries of the slot walls were optimized to find the maximum stall margin and pressure ratio of the compressor.
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June 2024
School of Mechanical Engineering & Automation, Northeastern University, Shenyang, 110819, Liaoning, China.
In the present study, a new turbomolecular pump (TMP) performance prediction algorithm is proposed according to the variable surface combined blade row (VSCBR) geometric model. The simulation calculation program is designed to perform structural optimization and flow field analysis. Research on the pumping performance of the traditional straight blade row (TSBR) indicates that when the blade velocity ratio is greater than 1, the increase in the pumping speed and compression ratio of the TMP gradually tends to stabilize.
View Article and Find Full Text PDFSurgical repair of acute or chronic lateral instability of the ankle may be unsuccessful in the presence of associated anterior fibulotalar ligament (AFTL) and calcaneofibular ligament (CFL) injury. This Technical Note presents an arthroscopic double-row repair technique of the AFTL associated with suture tape augmentation of the CFL. The patient is in the supine position with the ankle hanging over the edge of the surgical table.
View Article and Find Full Text PDFHeliyon
March 2024
School of Mechatronics Engineering, Anhui University of Science and Technology, 232001, Huainan, Anhui Province, China.
To meet the urgent need for a new design concept and solve the inaccuracy of existing performance prediction algorithms for high-speed turbomolecular pumps (TMPs), a new algorithm based on a novel twisted rotor blade is proposed. In this algorithm, the blade angle of the turbine rotor row progressively decreases from the root to the tip of the blade tooth. The feasibility and accuracy of the simulation algorithm were verified through experiments.
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