Acceleration-Based In Situ Eddy Dissipation Rate Estimation with Flight Data

Inducing civil aviation aircraft to bumpiness, atmospheric turbulence is a typical risk that seriously threatens flight safety. The Eddy Dissipation Rate (EDR) value, as an aircraft-independent turbulence severity indicator, is estimated by a vertical wind-based or aircraft vertical acceleration-based algorithm. Based on the flight data of civil aviation aircraft, the vertical turbulence component is obtained as the input of both algorithms. A new method of computing vertical acceleration response in turbulence is put forward through the Unsteady Vortex Lattice Method (UVLM). The lifting surface of the target aircraft is assumed to be a combination of wing and horizontal tail in a turbulent flight scenario. Vortex rings are assigned on the mean camber surface, forming a non-planar UVLM, to further improve the accuracy. Moreover, the neighboring vortex lattices are placed as close as possible to the structural edge of control surfaces. Thereby, a complete algorithm for estimating vertical acceleration and in situ EDR value from Quick Access Recorder (QAR) flight data is proposed. Experiments show that the aerodynamic performance is computed accurately by non-planar UVLM. The acceleration response by non-planar UVLM is able to track the recorded acceleration data with higher accuracy than that of the linear model. Different acceleration responses at different locations are also obtained. Furthermore, because the adverse effects of aircraft maneuvers are separated from turbulence-induced aircraft bumpiness, the new acceleration-based EDR algorithm shows better accuracy and stability.

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The Optimization of Aircraft Acceleration Response and EDR Estimation Based on Linear Turbulence Field Approximation

Atmosphere ◽

10.3390/atmos12060799 ◽

2021 ◽

Vol 12 (6) ◽

pp. 799

Author(s):

Debao Wang ◽

Zhenxing Gao ◽

Hongbin Gu ◽

Xinyu Guan

Keyword(s):

Field Approximation ◽

Civil Aviation ◽

Vertical Acceleration ◽

Acceleration Response ◽

Lattice Method ◽

Vortex Lattice Method ◽

Tail Assembly ◽

Turbulence Effects ◽

Air Compression ◽

Compression Effects

The estimation of aircraft vertical acceleration response to atmospheric turbulence is fundamental to acceleration-based eddy dissipation rate (EDR) estimation. The linear turbulence field approximation with the wind gradients effects is utilized to describe the turbulence effects on civil aviation aircraft. To consider the wind gradients effects, the aircraft was modeled by a cruciform assembly in this study. A vertical acceleration estimation based on the unsteady vortex lattice method (UVLM) was proposed, in which the air-compression effects in high-subsonic flight were compensated by the Karman–Tsien rule. Results indicate that compared with the wing-tail assembly, the cruciform assembly with the wind gradients effects has better accuracy in computing acceleration response. The vertical acceleration response only induced by turbulence can be obtained for acceleration-based EDR estimation. Furthermore, with the optimized acceleration response, the estimated EDR value has got better accuracy and stability.

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Estimation of Aircraft-Dependent Bumpiness Severity in Turbulent Flight

Applied Sciences ◽

10.3390/app11041796 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1796

Author(s):

Haofeng Wang ◽

Zhenxing Gao ◽

Hongbin Gu ◽

Kai Qi

Keyword(s):

Aerodynamic Force ◽

Estimation Method ◽

Control Surface ◽

Civil Aviation ◽

Vertical Acceleration ◽

Continuous Change ◽

Lattice Method ◽

Severity Estimation ◽

Surface Deflections

Atmospheric turbulence threatens flight safety of civil aviation aircraft by inducing aircraft bumpiness. A severity estimation method of aircraft bumpiness in turbulent flight is explored according to in-situ Eddy Dissipation Rate (EDR) indicator. With the turbulence intensity derived from EDR value, a time series of longitudinal and vertical turbulence was generated according to von Karman turbulence model. In order to obtain the vertical acceleration response of aircraft, the continuous change of aerodynamic force on the assembly of wing and horizontal tail was computed by Unsteady Vortex Lattice Method (UVLM). The computing accuracy was improved by using semi-circle division and assigning the vortex rings on the mean camber surface. Furthermore, the adverse effects of control surface deflections on bumpiness severity estimation can be effectively removed by separating turbulence-induced and aircraft maneuvers-induced aerodynamic force change. After that, the variance of vertical acceleration, as the severity indicator of aircraft bumpiness, was obtained by Welch spectrum estimation. With the refined grid level, the pitching moment change due to control surface deflections can be solved accurately by UVLM. The instantaneous acceleration change obtained by UVLM approximates recorded acceleration data with better accuracy than linear transfer function model. A further test with a set of flight data on the same airway shows that compared with in-situ EDR indicator, the proposed method gives an aircraft-dependent estimation of bumpiness severity, which can not only be used to estimate in-situ bumpiness but also be applied to forecast the bumpiness severity of other different aircrafts.

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A Comparison Study of EDR Estimates from the NLR and NCAR Algorithms

Atmosphere ◽

10.3390/atmos13010132 ◽

2022 ◽

Vol 13 (1) ◽

pp. 132

Author(s):

Jeffrey Chi Wai Lee ◽

Christy Yan Yu Leung ◽

Mang Hin Kok ◽

Pak Wai Chan

Keyword(s):

The Netherlands ◽

Real Time ◽

Dissipation Rate ◽

Vertical Acceleration ◽

Comparison Study ◽

Time Data ◽

Flight Data ◽

Atmospheric Research ◽

Real Time Data ◽

Good Agreement

A comparison was made of two eddy dissipation rate (EDR) estimates based on flight data recorded by commercial flights. The EDR estimates from real-time data using the National Center for Atmospheric Research (NCAR) Algorithm were compared with the EDR estimates derived using the Netherlands Aerospace Centre (NLR) Algorithm using quick assess recorder (QAR) data. The estimates were found to be in good agreement in general, although subtle differences were found. The agreement between the two algorithms was better when the flight was above 10,000 ft. The EDR estimates from the two algorithms were also compared with the vertical acceleration experienced by the aircraft. Both EDR estimates showed good correlation with the vertical acceleration and would effectively capture the turbulence subjectively experienced by pilots.

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A Method for Estimating Aircraft Vertical Acceleration and Eddy Dissipation Rate in Turbulent Flight

Applied Sciences ◽

10.3390/app10196798 ◽

2020 ◽

Vol 10 (19) ◽

pp. 6798

Author(s):

Zhenxing Gao ◽

Debao Wang ◽

Zhiwei Xiang

Keyword(s):

Dissipation Rate ◽

Aerodynamic Force ◽

Wind Tunnel Test ◽

Control Surface ◽

Civil Aviation ◽

Vertical Acceleration ◽

Pitching Moment ◽

Continuous Change ◽

Adverse Influence ◽

Modeling Data

Atmospheric turbulence is a typical risk that threatens the flight safety of civil aviation aircraft. A method of estimating aircraft’s vertical acceleration in turbulence is proposed. Based on the combination of wing and horizontal tail, the continuous change of aerodynamic force in turbulent flight is obtained by unsteady vortex ring method. Vortex rings are assigned on the mean camber surface to further improve the computing accuracy. The incremental aerodynamic derivatives of lift and pitching moment are developed, which can describe the turbulence effects on aircraft. Furthermore, a new acceleration-based eddy dissipation rate (EDR) algorithm was developed to estimate the turbulence severity. Compared with wind tunnel test data, the aerodynamic performance of the lifting surface was computed accurately. A further test on wing–tail combination showed that the computed pitching moment change due to control-surface deflections approaches the aircraft-modeling data. The continuous change of vertical acceleration at any longitudinal locations of aircraft is obtained in turbulent flight. Compared with traditional transfer function-based EDR algorithms, the proposed algorithm shows higher accuracy and stability. Furthermore, the adverse influence of aircraft maneuvering on EDR estimation is eliminated.

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Retrieval of Eddy Dissipation Rate from Derived Equivalent Vertical Gust included in Aircraft Meteorological Data Relay (AMDAR)

10.5194/amt-2019-442 ◽

2019 ◽

Author(s):

Soo-Hyun Kim ◽

Hye-Yeong Chun ◽

Jung-Hoon Kim ◽

Robert D. Sharman ◽

Matt Strahan

Keyword(s):

Dissipation Rate ◽

Meteorological Data ◽

Civil Aviation ◽

Cube Root ◽

Control Procedures ◽

Turbulence Data ◽

Upper Level ◽

Best Fit ◽

Mapping Scheme

Abstract. Some of the Aircraft Meteorological Data Relay (AMDAR) data include a turbulence metric of the derived equivalent vertical gust (DEVG), in addition to wind and temperature. As the cube root of the eddy dissipation rate (EDR) is the International Civil Aviation Organization standard turbulence reporting metric, we attempt to retrieve the EDR from the DEVG for more reliable and consistent observations of aviation turbulence globally. Using the DEVG in the AMDAR archived from October 2015 to September 2018 covering a large portion of the Southern Hemisphere and North Pacific and North Atlantic Oceans, we convert the DEVG to the EDR using two methods, after conducting quality control procedures to remove suspicious turbulence reports in the DEVG. The first method is to remap the DEVG to the EDR using a lognormal mapping scheme, while the second one is using the best-fit curve between the EDR and DEVG developed in the previous study. The DEVG-derived EDRs obtained from the two methods are evaluated against in situ EDR data reported by United States-operated carriers. For two specified regions of the trans-Pacific Ocean and Europe, where both the DEVG-derived EDRs and in situ EDRs were available, the DEVG-derived EDRs obtained by the two methods are generally consistent with in situ EDRs, with slightly better statistics by the first method than the second one. This result is encouraging for extending the aviation turbulence data globally with the single preferred EDR metric, which will contribute to the improvement of global aviation turbulence forecasting as well as to the construction of the climatology of upper-level turbulence.

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Retrieval of eddy dissipation rate from derived equivalent vertical gust included in Aircraft Meteorological Data Relay (AMDAR)

Atmospheric Measurement Techniques ◽

10.5194/amt-13-1373-2020 ◽

2020 ◽

Vol 13 (3) ◽

pp. 1373-1385 ◽

Cited By ~ 1

Author(s):

Soo-Hyun Kim ◽

Hye-Yeong Chun ◽

Jung-Hoon Kim ◽

Robert D. Sharman ◽

Matt Strahan

Keyword(s):

Dissipation Rate ◽

Meteorological Data ◽

Civil Aviation ◽

Cube Root ◽

The Pacific ◽

Control Procedures ◽

Turbulence Data ◽

The Pacific Ocean ◽

Upper Level

Abstract. Some of the Aircraft Meteorological Data Relay (AMDAR) data include a turbulence metric of the derived equivalent vertical gust (DEVG), in addition to wind and temperature. As the cube root of the eddy dissipation rate (EDR) is the International Civil Aviation Organization standard turbulence reporting metric, we attempt to retrieve the EDR from the DEVG for more reliable and consistent observations of aviation turbulence globally. Using the DEVG in the AMDAR data archived from October 2015 to September 2018 covering a large portion of the Southern Hemisphere and North Pacific and North Atlantic oceans, we convert the DEVG to the EDR using two methods, after conducting quality control procedures to remove suspicious turbulence reports in the DEVG. The first method remaps the DEVG to the EDR using a lognormal mapping scheme, while the second one uses the best-fit curve between the EDR and DEVG developed in a previous study. The DEVG-derived EDRs obtained from the two methods are evaluated against in situ EDR data reported by US-operated carriers. For two specified regions of the Pacific Ocean and Europe, where both the DEVG-derived EDRs and in situ EDRs were available, the DEVG-derived EDRs obtained by the two methods were generally consistent with in situ EDRs, with slightly better statistics obtained by the first method than the second one. This result is encouraging for extending the aviation turbulence data globally with the single preferred EDR metric, which will contribute to the improvement of global aviation turbulence forecasting as well as to the construction of the climatology of upper-level turbulence.

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Generalized vortex lattice method for planar supersonic flow

AIAA Journal ◽

10.2514/3.13655 ◽

1997 ◽

Vol 35 ◽

pp. 1230-1233

Author(s):

Paulo A. O. Soviero ◽

Hugo B. Resende

Keyword(s):

Supersonic Flow ◽

Vortex Lattice ◽

Lattice Method ◽

Vortex Lattice Method

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Static Aeroelastic Characteristics of Morphing Trailing-Edge Wing Using Geometrically Exact Vortex Lattice Method

International Journal of Aerospace Engineering ◽

10.1155/2019/5847627 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15

Author(s):

Sen Mao ◽

Changchuan Xie ◽

Lan Yang ◽

Chao Yang

Keyword(s):

Vortex Lattice ◽

Deflection Angle ◽

Aircraft Design ◽

Analysis Method ◽

Lattice Method ◽

Trailing Edge ◽

Vortex Lattice Method ◽

Analysis And Design ◽

Aeroelastic Analysis ◽

Typical Model

A morphing trailing-edge (TE) wing is an important morphing mode in aircraft design. In order to explore the static aeroelastic characteristics of a morphing TE wing, an efficient and feasible method for static aeroelastic analysis has been developed in this paper. A geometrically exact vortex lattice method (VLM) is applied to calculate the aerodynamic forces. Firstly, a typical model of a morphing TE wing is chosen and built which has an active morphing trailing edge driven by a piezoelectric patch. Then, the paper carries out the static aeroelastic analysis of the morphing TE wing and corresponding simulations were carried out. Finally, the analysis results are compared with those of a traditional wing with a rigid trailing edge using the traditional linearized VLM. The results indicate that the geometrically exact VLM can better describe the aerodynamic nonlinearity of a morphing TE wing in consideration of geometrical deformation in aeroelastic analysis. Moreover, out of consideration of the angle of attack, the deflection angle of the trailing edge, among others, the wing system does not show divergence but bifurcation. Consequently, the aeroelastic analysis method proposed in this paper is more applicable to the analysis and design of a morphing TE wing.

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