Accurate Monotone Cubic Interpolation

Huynh, H. T.

doi:10.1137/0730004

Cited by 103 publications

(56 citation statements)

References 22 publications

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“…The outer background meshes communicate with each other by means of a sliding mesh interface as explained earlier, allowing for a complete simulation using just one blade mesh in each rotor system. The solution is transferred from one mesh to the other by using a third order slope limited M3-quartic interpolation of Huynh [91].…”

Section: Mesh Systemmentioning

confidence: 99%

Computational Investigation of Microscale Coaxial-Rotor Aerodynamics in Hover

Lakshminarayan

Baeder

2010

Journal of Aircraft

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In this work, a compressible Reynolds-Averaged Navier Stokes (RANS) solver is extended to investigate the aerodynamics of a micro-scale coaxial rotor configuration in hover. This required the following modifications to the solver: implementation of a time-accurate low Mach preconditioner, implementation of a sliding mesh interface boundary condition, improvements in the grid connectivity and parallelization of the code.First, an extensive validation study on the prediction capability of the solver is performed on a hovering micro-scale single rotor, for which performance data and wake characteristics have been measured experimentally. The thrust and power are reasonably well predicted for different leading and trailing geometries.Blunt leading edge geometries show poorer performance compared to the sharp leading edge geometries; the simulations show that this is mainly because of the large pressure drag acting at the blunt front. The tip vortex trajectory and velocity profiles are also well captured. The predicted swirl velocities in the wake for the micro-rotor are found to be significantly larger as compared to those for a full-scale rotor, which could be one of the reasons for additional power loss in the smaller scale rotors. The use of twist and taper is studied computationally and is seen to improve the performance of micro-rotor blades.Next, the solver is applied to simulate the aerodynamics of a full-scale coaxial rotor configuration in hover, for which performance data is available from experiments. The global quantities such as thrust and power are predicted reasonably well. In the torque trimmed situation, the top rotor shares significant percentage of the total thrust at lower thrust levels, which decreases to about 55% of the total thrust at higher thrust values. The simulations reveal that the interaction between the rotor systems is seen to generate significant impulses in the instantaneous thrust and power. The characteristic signature of this impulse is explained in terms of the blade thickness effect and loading effect, as well as blade-vortex interactions for the bottom rotor (wake effect).Finally, the RANS solver is applied to investigate the aerodynamics of a micro-scale coaxial rotor configuration in hover. The overall performance is well predicted. The interaction between the rotor systems is again seen to generate 3-8% fluctuation in the instantaneous thrust and power. The wake effect in the simulation is seen to be very prominent and the phasing of the impingement of the tip vortex from the top rotor upon the bottom rotor plays a significant role in the amount of unsteadiness on the bottom rotor. Interaction of the top rotor vortex and inboard sheet with the bottom rotor results in significant shedding on the bottom rotor blade, and this is believed to be caused by the of sharp leading edge geometry. Significant blade-vortex and vortex-vortex interactions are observed for coaxial systems.

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Section: Mesh Systemmentioning

confidence: 99%

Computational Investigation of Microscale Coaxial-Rotor Aerodynamics in Hover

Lakshminarayan

Baeder

2010

Journal of Aircraft

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“…Accuracy and monotonicity preservation are somewhat conflicting requirements. We review below some known results concerning Monotone Hermite Interpolation and refer the interested reader to [10,19,22], and references therein for further information on this subject.…”

Section: Monotonicity-preserving Hermite Interpolationmentioning

confidence: 99%

“…To ensure monotonicity, additional constraints on the {ḟ i } values are required, [10,19,22]. Among these constraints, the simplest one (and probably the most used) is the de-Boor and Swarz condition [10],…”

Section: Monotonicity-preserving Hermite Interpolationmentioning

confidence: 99%

The PCHIP subdivision scheme

Aràndiga

Donat

Santágueda

2016

Applied Mathematics and Computation

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“…A preprocessor is needed to re-arrange the flight variables in the dataset, and interpolate the variables if necessary by a monotone cubic spline [9]. For example, the FDR data can provide the necessary data to develop models for pilot training and flight control development.…”

Section: B Flight Control Modelmentioning

confidence: 99%

Artificial Intelligence Applications of Hazardous Mitigation for Transport Aircraft in Severe Atmospheric Turbulence

Chang¹

2016

Proceedings of the 2016 2nd International Conference on Artificial Intelligence and Industrial Engineering (AIIE 2016)

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Abstract-This paper presents a new study of artificial intelligence applications through the simulation of improved control strategy to provide the mitigation concepts and formulate preventive actions for aircraft operation. The fuzzy-logic modeling (FLM) technique is used to establish flight control models with the function of nonlinear dynamic inversion based on the datasets from the flight data recorder (FDR). The improved control strategy can be obtained through the simulations of flight control models to enhance the stability and controllability before and during the severe atmospheric turbulence.

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Accurate Monotone Cubic Interpolation

Cited by 103 publications

References 22 publications

Computational Investigation of Microscale Coaxial-Rotor Aerodynamics in Hover

Computational Investigation of Microscale Coaxial-Rotor Aerodynamics in Hover

The PCHIP subdivision scheme

Artificial Intelligence Applications of Hazardous Mitigation for Transport Aircraft in Severe Atmospheric Turbulence

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