Computational Investigation on Unsteady Loads of High-Speed Rigid Coaxial Rotor with High-Efficient Trim Model

Qi, Haotian; Xu, Guohua; Lu, Congling; Shi, Yongjie

doi:10.1007/s42405-018-0133-0

Cited by 9 publications

(8 citation statements)

References 21 publications

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“…The CFD solver and trim model used in this paper have been validated through different experimental cases (see Refs. [18,19]), which show reasonable accuracy in the prediction of aerodynamic performance. Current existing experiments are mostly about the aerodynamics of coaxial rotors [29,30].…”

Section: Validation Casesmentioning

confidence: 77%

“…The CFD solver used in this paper was developed in Refs. [18,19]. Navier-Stokes equations [21] in an inertial Cartesian coordinate system are employed to simulate the rotor flow field, which can be written as…”

Section: Cfd Methods and Trim Modelmentioning

confidence: 99%

“…A detailed introduction to the trim model can be found in Refs. [18,19]. The trimmed collective pitches for various rotor thrusts in hover are given in Table 2.…”

Section: Cfd Methods and Trim Modelmentioning

confidence: 99%

“…Thus, for the hover state, it is necessary to carry out a further analysis on the aerodynamic noise of a coaxial rotor, referring to the mechanism of interaction. This paper is further research based on the previous research [18,19]. The previous CFD solver based on the RANS solver and moving overset mesh are adopted for flow field simulation, which provides sound source information.…”

Section: Introductionmentioning

confidence: 99%

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Investigation on Aerodynamic Noise Characteristics of Coaxial Rotor in Hover

Wang

Jiang

et al. 2022

Applied Sciences

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A numerical method based on Reynolds Averaged Navier–Stokes (RANS) equations and a high-efficiency trim model is developed to simulate the aerodynamics of a coaxial rotor. Farassat 1A equations are used for the prediction of thickness and loading noise. Hover cases of different thrust coefficients with torque balance are conducted. The sound pressure history of different observation points positioned below the rotor disk plane is analyzed. Results indicate that the special noise characteristics of the coaxial rotor are mainly caused by the noise superposition of the twin rotors and the unsteady loads of aerodynamic interaction. A new kind of impulsive loading noise is induced by the blade-meeting interaction. In contract to the single rotor, the loading noise of a coaxial rotor has a much larger sound pressure level in the high-frequency band. The loading noise is obviously enhanced around the blade-meeting azimuths. The maximum noise of the coaxial rotor is located immediately below the rotor disk center, while for the single rotor, it is the minimum location.

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Section: Validation Casesmentioning

confidence: 77%

Section: Cfd Methods and Trim Modelmentioning

confidence: 99%

“…A detailed introduction to the trim model can be found in Refs. [18,19]. The trimmed collective pitches for various rotor thrusts in hover are given in Table 2.…”

Section: Cfd Methods and Trim Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigation on Aerodynamic Noise Characteristics of Coaxial Rotor in Hover

Wang

Jiang

et al. 2022

Applied Sciences

Self Cite

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“…Meanwhile, some improved trim methods for rotor aerodynamic analysis are proposed which can not only compute the aerodynamic interference accurately and improve the computational efficiency at the same time. Ye 19 and Qi 20,21 proposed a high-efficiency improved delta trim method for helicopter rotors. Bhagwat 22 and Su 23 put forward a "relaxation difference" based trim strategy to reduce the calculation time during trim iteration.…”

Section: Introductionmentioning

confidence: 99%

Flight dynamics analysis of a small tandem helicopter considering aerodynamic interference

Duan

Ding

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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The interference calculation is essential to the flight dynamic analysis especially for multi-rotors configurations. To analyze the flight dynamic characteristics of a small tandem helicopter precisely, a vortex method is utilized to obtain the aerodynamic interaction between the tandem rotors and the fuselage. Specially, the unsteady air loads and the wake of the rotors are developed using a lifting surface method and the viscous vortex particle theory, respectively, and the fuselage is modeled by the panel method to simulate the blocking effect on the rotors. Then the aerodynamic interference of the small tandem helicopter is analyzed under the conditions of different vertical or horizontal distance between the rear and front rotors. Subsequently, to save calculation time during flight dynamic analysis, a hybrid optimization trimming method combining the equilibrium optimizer and the improved delta method is proposed. At last, the flight dynamic analysis for the small tandem helicopter with different configurations are carried out and the results indicate that configuration in which the rear rotor is located higher than the front rotor and the one with larger longitudinal distance between tandem rotors are beneficial to increase the stability in lateral and longitudinal directions, respectively.

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Natural products as Zika antivirals

Fong

Chu

2022

Medicinal Research Reviews

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Zika virus (ZIKV) is an arbovirus belonging to the flavivirus genus and is transmitted in Aedes mosquito vectors. Since its discovery in humans in 1952 in Uganda, ZIKV has been responsible for many outbreaks in South America, Africa, and Asia. Patients infected with ZIKV are usually asymptomatic; mild symptoms include fever, joint and muscle pain, and fatigue. However, severe infections may have neurological implications, such as Guillain-Barré syndrome and fetal microcephaly. To date, there are no existing approved therapeutic drugs or vaccines against ZIKV infections; treatments mainly target the symptoms of infection.Preventive measures against mosquito breeding are the main strategy for limiting the spread of the virus. Antiviral drug research for the treatment of ZIKV infection has been rapidly developing, with many drug candidates emerging from drug repurposing studies, and compound screening. In particular, several studies have demonstrated the potential of natural products as antivirals for ZIKV infection. Hence, this paper will review recent advances in natural products in ZIKV antiviral drug discovery.

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Computational Investigation on Unsteady Loads of High-Speed Rigid Coaxial Rotor with High-Efficient Trim Model

Cited by 9 publications

References 21 publications

Investigation on Aerodynamic Noise Characteristics of Coaxial Rotor in Hover

Investigation on Aerodynamic Noise Characteristics of Coaxial Rotor in Hover

Flight dynamics analysis of a small tandem helicopter considering aerodynamic interference

Natural products as Zika antivirals

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