Journal of Aeronautics, Astronautics and Aviation
- OpenAccess
Aeronautical and Astronautical Society of the Republic of China,正常發行
選擇卷期
- 期刊
- OpenAccess
In-flight seating comfort has been an important decision factor for many air transport passengers in choosing the offered flight services. The provision of good seating comfort increases the possibility of returning passengers and their loyalty towards the airlines. In general, the in-flight seating comfort can be affected by various factors including seat pitch and anthropometry of the passengers. To study the influences of these parameters, a sitting experiment is done in aircraft cabin mock-up. 30 volunteers of different anthropometric dimensions have participated in this study and the seat pitch setting is varied at six different values between 26 inches (66.04 cm) to 41 inches (104.14 cm). Based on ANOVA results of comfort assessment ratings given by participants, seat pitch is shown to be the most influential factor for seating comfort with 94.02% contribution to its rating. In the meantime, five top influential sitting posture anthropometric measurements are forward grip reach, elbow height, buttock knee length, crown buttock height and shoulder height, which have a cumulative 5.03% contribution to the variability in the seating comfort rating. A regression model to capture the underlying relationship between the seating comfort and these influential factors has been constructed.
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- OpenAccess
An accurate localization of unmanned aerial vehicles (UAVs) is crucial for the execution of its growing applications such as surveillance and rescue missions. Previous researches have extensively studied the usage of sensor fusion algorithms to combine the sensors on board of the UAV to improve its localization. However, application of collaborative localization techniques in UAV navigation has not been investigated thus far. These novel algorithms stand to improve the stability and accuracy of UAV localization approaches through incorporation of additional sensors from other moving targets such as an unmanned ground vehicle (UGV). It is believed that the accuracy of the UAV localization will be further improved with help of multi-sensor Kalman filter (MS-KF) and this collaborative sensor fusion approach leads to a better accuracy than that of the single-sensor Kalman filter (SS-KF) approach. The obtained results in this study show promising improvements of both position and attitude with MS-KF. In comparison, the mean square error (MSE) for position is 0.005 and 0.026 for the developed MS-KF and SS-KF, respectively. Meanwhile, MSE for attitude is 2.396e-5 and 8.11e-4 for the developed MSKF and SS-KF, respectively. Based on these findings, the positive potential of collaborative sensor fusion approach has been aptly highlighted.
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- OpenAccess
A wing-in-ground effect (WIG) craft experiences longitudinal instability due to its center of pressure (COP) location migrating when in transition from in-ground-effect (IGE) to out-of-ground effect (OGE) zone. The study on this subject has always been a grey area and only very limited published research is available. As an attempt to further support the development of WIG crafts, this study investigates COP migration for different wing configurations using CFD software. It is taken that a satisfying configuration must have a minimal COP migration in term of the vertical height as percentage of chord (HC) and angle of attack (AOA) increment. The significant severances of ground effect depend on the total COP migration from 0◦ to 10°. With this notion, the cases of rectangular and inverse delta wing configurations have been simulated and analyzed using two different airfoil profiles: Clark Y and DHMTU. The COP for each configuration is plotted and based on the analysis results, it is found the COP migration is relatively higher for the rectangular wing configurations that the inverse delta wing configurations. The lowest COP migration is for the inverse delta wing with DHMTU airfoil while the highest migration is for the rectangular wing with DHMTU airfoil.
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This paper presents a review on the aerodynamic characteristics of insect flight. The goal of this review is to highlight the areas where advancement is required, i.e. nature-inspired lift enhancement mechanisms. Various aspects of the insect flight aerodynamics are covered in this paper, which includes the general overview or introduction of flapping wing insect flight, production or formation of wing vortices during continuous flapping motion, extraction of energy from the wing's own wake, aspects of wing flexibility that might assist in increasing the thrust force, factors influencing aerodynamic performance during wing rotation, aspects of wing shape for structural integrity as a natural outcome of power available and lift force required to sustain in flight, tandem wing configuration and also wing corrugation. To summarize these findings, this review paper concludes with the discussions on the essential features of the aerodynamic characteristics of the nature-inspired insect flight, including identification of main factors, effects and lift enhancement mechanisms that go beyond the traditional aerodynamic theory and might be easily applied to improve the flight aerodynamic performance. This knowledge is particularly useful for future development and research in this field of study.
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This study will focus on technologies and applications that have excelled in many other industries but yet to be applied in aviation, which is waste heat recovery technology with supercritical carbon dioxide (sCO_2) as the cycle's working fluid. In this case, this technology can help to reduce the jet engines' fuel consumption, and minimize fuel expenses and also carbon dioxide (CO_2) emissions. The analysis of sCO_2 cycle that is thermodynamically integrated into a turbofan jet engine is conducted via simulation within the Aspen Plus software and the Microsoft Excel is used for the post-processing of the results. Moreover, a quantitative analysis is done to select the best performing sCO_2 cycle configuration based on the jet engine's performance increment after the cycle's integration as its waste heat recovery system. All in all, the obtained results show that recuperation cycle (42.46%, 2197.67 kW) performs much better than basic Brayton cycle (18.53 %, 2555.84 kW) in terms of thermal efficiency and network. As for jet engine performance, integrating the basic Brayton cycle has generated greater thrust specific fuel consumption (TSFC) savings of 13.91% with improved value of 1.7474 kg/s/kN compared to the recuperation cycle savings of 7.06% and improved value of 1.8865 kg/s/kN.
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- OpenAccess
Aircraft structures are often subjected to many complex loads that even a minor structural damage can disrupt their load-bearing capacities and lead to catastrophic failure. Ultrasonic wavefield inspection has been available for a while and it is a great method for damage detection. However, the challenge lies in the complexity of the algorithm for mode isolation. For this study, the damage visualization is performed based on frequency shift of single-mode ultrasound-guided wavefield. In principle, the spatio-temporal wavefield data is transformed into the wavenumber-temporal domain and filtering is then performed using Boxcar window before mapping the data. First, a filter width for mode isolation of ultrasonic wavefield in a time-cumulated wavenumber plane is determined. Then, generation of frequency map based on ultrasound spectral imaging (USI) for damage identification is investigated. Last but not least, the comparison of accuracy between frequency analysis algorithm and variable time window amplitude mapping (VTWAM) algorithm is performed. This technique is evaluated to detect artificial damages of 2 mm and 30 mm diameter in steel plates. Overall, the results show that frequency analysis can detect the damage four times faster and the algorithm uses two-dimensional calculation instead of conventional three-dimensional of VTWAM method.
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- OpenAccess
The variable ribs' orientation concept is becoming one of the promising options for innovative wing box design for aircraft whereby several previous studies have shown that significant improvement in aeroelastic characteristics can be acquired without any increment in weight. This paper presents further investigation that has been conducted with respect to strain energy of flutter modes. Two different untapered wing-box configurations of the unswept and sweptback planforms are considered and the comparison is made between the best-found solution against the reference baseline configuration. Based on the findings, the strain energy is found at a greater magnitude for the variable ribs that are located between the middle section and the root section of the wing. This demonstrates significant stiffness improvement that is contributed by the ribs at this location.
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This study proposes a crop-spraying module that is detachable and can be used with any multirotor drone system with larger than 600-mm diagonal diameter. The module is designed to independently operate and can instantly connect to a smartphone as it is Bluetooth-controlled. The spraying system is controlled using an Arduino microcontroller, which is connected to MDD3A motor driver for 12-V pump and also HC-05 Bluetooth module for wireless system control via smartphone. In this study, the low-cost Tarot X6 multirotor drone kit has been used as the system platform for the module development. During the hover flight test, the system is tested at three pump voltage settings and two altitudes to determine its operational capabilities. The flight test is conducted with a flying speed of 7.0 m/s and altitude of 1.4 m above ground, where the mission is observed and the total area covered by sprayed colored water per flight is estimated. The observed mission performance is compared with that of some commercial agriculture drones. Overall, it can be taken that the unit cost of this developed crop-spraying module with Tarot X6 drone is considered low cost though its performance is found to be slightly inferior to the commercial ones.
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This paper presents a numerical method investigation on the aerodynamic performance of a small-scale propeller with four different shapes of propeller design using computational fluid dynamic (CFD). In this study, the relationship between varying airfoil's origin position (AOP) at each station and resultant aerodynamics performance is investigated. Several designs of the propellers are derived by changing the AOP at each blade station with the percentage of 0% AOP, 25% AOP, 50% AOP, 75% AOP and 100% AOP. The result of thrust, power coefficients and efficiencies are validated with the existing experimental wind tunnel data. All in all, the results show that propeller design with 100% AOP generates better aerodynamic performance than the one with 25% AOP by 7.473%, -5.587% and 15.891% in terms of thrust, coefficient of power and efficiency, respectively. It has also been found that the propeller design with 100% AOP has a better aerodynamics performance compared to the 25% AOP, 50% AOP and 75% AOP, especially at an advanced ratio of 0.799. Overall, it can be concluded that the improvement in terms of aerodynamic characteristics and performance is possible by increasing the position of the blade origin at each station, which in turn results in different propeller design shapes.