Sensitivity analysis on the model input parameters of flapping wing kinematics for optimum level flight via particle swarming optimization

A systematic reviewing process to assess the sensitivity of the input parameters of flapping wing kinematics for optimum level flight is presented. This is done prior to the development of a stroke optimization model to predict the aerodynamic performance of an insect (hawk moth) during flight. A systematic iterative process-population-based stochastic algorithm, known as particle swarming optimization, is used. In the search for an optimal realistic wing kinematic motion, several constraints for stable flight are defined following the observational wing kinematics data from experiments on real insects. This is to avoid any physically-unrealistic solutions of the wing motion. Two stages of sensitivity analyses are conducted via partial sensitivity analysis, or one-at–a-time. First, sensitivity screening analyses are performed to gauge the dependability of the solution output, i.e. total force and total power, on each model input parameter; a total of 9 model input parameters. Then, the second stage of sensitivity analysis to measure on how the most sensitive model input parameters will affect the optimized kinematics are conducted. The results have shown that the wing length and the wing translational lift coefficient are the most sensitive aerodynamic model input parameters among other inputs

Overview of Coandă jet lift enhancement and two-dimensional computational studies

Motivated by attempts to enhance wind-turbine aerodynamic performance and efficiency, Coandă Jet Lift Enhancement for Circulation Control that has drawn great attention from researchers and industries is investigated numerically. Coandă Jet Circulation Control Techniques has a long history of development, although meticulous Modelling and innovations for practical applications for energy conversion (such as for wind-turbine applications), aircraft wing lift enhancement and propulsion (such as for Coandă -MAV) are continually in progress. Along this line, the influence of Coandă effect for lift generation and enhancement is here investigated using two-dimensional CFD simulation. To that end, attention is focussed on Coandă jet configuration located at the trailing edge, to reveal the key elements that could exhibit the desired performance criteria for lift enhancement and drag reduction, or a combination of both. Parametric studies are carried out to obtain some optimum configuration, by varying pertinent airfoil geometrical and Coandă jet parameters. Particular attention is also given to turbulence modelling, by meticulous choice of appropriate turbulent models and scaling, commensurate with the grid generation, CFD code utilized and computational effectiveness. The present two-dimensional Coandă jet studies are carried out with wind turbine and micro-air-vehicle design in view, and discussed in the light of recent results from similar research

NUMERICAL SIMULATION AND ANALYSIS OF COANDA EFFECT CIRCULATION CONTROL FOR WIND-TURBINE APPLICATION CONSIDERATIONS

In the efforts to investigate the performance of Coanda Jet in enhancing lift of an airfoil, a numerical study is carried out. Tangential jets that take advantage of Coanda effect to closely follow the contours of the body are considered to be simple and particularly effective in that they can entrain a large mass of surrounding air. This can lead to increased circulation in the case of airfoils, or drag reduction (or drag increase if desired) in the case of bluff bodies such as an aircraft fuselage. Critical review and analysis is also carried out for the application of Coanda Jet to optimize the aerodynamic performance of wind turbine, using the results of the numerical study and taking advantage of recent efforts to introduce Coanda effect as a novel circulation control technique. For this purpose a simple two-dimensional CFD modeling is utilized to reveal the key elements that could exhibit the desired performance criteria, in particular the lift enhancement and drag reduction, or a combination of both. Three dimensional configurations will be synthesized using certain acceptable assumptions, to compare such results with existing experimental data. Hence in this work the problem is idealized as basic airflow over a two-dimensional airfoil in subsonic flow; by the use of CFD technique, parametric study is carried out to arrive at plausible design considerations and to assess the practicability of Coanda jet in wind turbine design. Parametric study carried out shows the effectiveness of Coanda-jet in producing enhanced lift, which can contribute to increased torque in wind turbine application and increased axial thrust for propeller application. The numerical study also shows that appropriate trailing edge rounding off and tailoring the Coanda-jet thickness and momentum coefficient can produce enhanced lift to drag ratio. ABSTRAK : Dalam usaha untuk mengkaji prestasi Coanda Jet bagi mempertingkatkan daya angkat suatu aerofil, kajian berangka telah dijalankan. Tangen jet yang mengambil manfaat efek Coanda mengikut kontur permukaan dianggap mudah dan berkesan kerana ia dapat mengiring satu jisim besar udara sekeliling. Ini mendorong kepada penambahan edaran udara dalam kes aerofil, atau penurunan seret (juga penambahan seret jika diingini) dalam kes jasad tubir seperti fiuslaj pesawat. Ulasan kritikal dan analisis telah dijalankan bagi aplikasi Coanda Jet untuk mengoptimumkan prestasi aerodinamik turbin angin, menggunakan keputusan kajian berangka dan mengambil manfaat usaha memperkenalkan penggunaan efek Coanda sebagai satu teknik pengawalan edaran udara. Untuk tujuan ini, permodelan dua dimensi CFD telah digunakan untuk mendedahkan punca utama elemen yang dapat mededahkan kriteria prestasi yang diingini, khususnya peningkatan daya angkat dan penurunan seret, ataupun kombinasi kedua-duanya. Konfigurasi tiga dimensi akan disintesis menggunakan beberapa andaian yang boleh diterima, untuk membandingkan keputusan tersebut dengan data eksperimental yang sedia ada. Permasalahan dalam kajian ini diunggulkan sebagai aliran udara asas subsonik di atas aerofil dua dimensi; dengan menggunakan teknik CFD, kajian berparameter dijalankan untuk mendapat reka bentuk yang munasabah, dan mengkaji kebolehlaksanaan Coanda jet dalam reka bentuk turbin angin. Kajian berparameter menunjukkan keberkesanan Coanda-jet dalam menghasilkan peningkatan daya angkat, justeru menyumbangkan kepada peningkatan daya kilas dalam aplikasi turbin angin, dan juga penambahan tujah paksi dalam aplikasi bebaling. Kajian berangka ini juga menunjukkan pembundaran pinggir mengekor, pemilihan ketebalan Coanda-jet dan pekali momentum yang sesuai, akan menghasilkan peningkatan nisbah daya angkat terhadap seretan

Improving the stiffness of multilayer 3D woven composites by the integration of shape memory alloys (SMAs) into structures

Shape memory alloys (SMAs) are capable of shape-retaining and stress generation when activated. SMA wires are embedded in laminated composites for improving the properties of the composites. Laminated composites have low through-the-thickness properties and poor delamination resistance. 3D composites are well known for having higher through-the-thickness properties. In 3D woven composites, a set of yarn is in through-the-thickness direction that improves through-the- thickness properties and provides resistance to delamination of layers. As in multilayer 3D woven structures, yarns are distributed from in-plane to through-the-thickness direction, so in-plane properties are reduced with the same number of yarns compared to 2D laminated composites. In this research, SMA wires are embedded into different types of 3D woven structures for utilising stress generation property of SMA wires for improving in-plane properties, specifically stiffness of the composites. Three types of 3D orthogonal interlocking composites: layer-to-layer, through-the-thickness, and modified multilayer interlock structures are fabricated with and without SMA wires. From the tensile test, results show that embedding SMA wires into structures significantly improves the stiffness of the structures due to the stress-induced martensite phase of SMA wire when subjected to load. When these SMA wires are activated, stresses are generated by SMA wires due to phase transformation from martensite to austenite that further gives remarkable higher values of stiffness. This results in a composite structure that has higher in-plane properties due to embedded SMA wire and through-the-thickness properties due to 3D structure of composite reinforcement. The interlocking pattern in the through-the-thickness direction of 3D structures was also found to have an effect on the extent of the improvement in stiffness

Circulation control aircraft design: assessment on the channel-wing lift-thrust performance characteristics

Channel-wing has the ability to exceed the performance of conventional aircraft wing design; allowing for short take-off, overcome the needs for expensive conventional long runway setup and potential to decrease the aircraft running cost (e.g. flight duration, fuel usage). Assessment on the aerodynamic lift and propulsive thrust of three different sizes of the channel-wing design is carried out. The aim of the study is to provide an understanding of the channel-wing lift-thrust performance characteristics with the changes of the wing sizing (i.e. wing chord length). Fabrication of the channel-wing models was executed via 3D printer machine and the measured forces were analyzed using multiple load-cells and a microcomputer setup. All of the measurements are done in a controlled environment, and the channel-wings were tested at zero forward speed and at zero angles of attack. Indeed, the high speed rotating propeller mounted at the trailing edge of the wing generates a suction effect, reducing the pressure on the upper surface of the channel wing, producing lift. The results have shown that with a larger channel-wing size, the lift to thrust ratio can reach over 30%, however, when evaluating on the lift coefficient, the small channel-wing size is by far the most efficient. The amount of lift force generated and the reductions in the net thrust are found both dependents on the sizing of the channel-wing; longer wing chord promotes higher generations of lift, however, at the expense of some fraction of thrust

Masjid Besi, Putrajaya: Rekabentuk dan hubungannya dengan senibina Islam

Masjid Tuanku Mizan Zainal Abidin also known as Masjid Besi located in Precint 3, Putrajaya, Malaysia is built based on design modern contemporary and Islamic architecture.This mosque is the one only mosque which uses 6000 tonnes of steel or 70 percent building material during the construction, thus it is known as Masjid Besi. This study found that, this masjid is not one hundred percent based on Islamic architecture because is it more incline to modern design.Therefore, this paper will discuss the design of the Masjid Besi design architecture, by examining the relationship Islamic architectural with other elements influences exist on mosque architecture

Computational study on the aerodynamic performance of wind turbine airfoil fitted with Coandă jet

Various methods of flow control for enhanced aerodynamic performance have been developed and applied to enhance and control the behavior of aerodynamic components. The use of Coandă effect for the enhancement of circulation and lift has gained renewed interest, in particular with the progress of CFD. The present work addresses the influence, effectiveness, and configuration of Coandă-jet fitted aerodynamic surface for improving lift and , specifically for S809 airfoil, with a view on its incorporation in the wind turbine. A simple two-dimensional CFD modeling using - turbulence model is utilized to reveal the key elements that could exhibit the desired performance for a series of S809 airfoil configurations. Parametric study performed indicates that the use of Coandă-jet S809 airfoil can only be effective in certain range of trailing edge rounding-off radius, Coandă-jet thickness, and momentum jet size. The location of the Coandă-jet was found to be effective when it is placed close to the trailing edge. The results are compared with experimental data for benchmarking. Three-dimensional configurations are synthesized using certain acceptable assumptions. A trade-off study on the S809 Coandă configured airfoil is needed to judge the optimum configuration of Coandă-jet fitted Wind-Turbine design

Lift force for cylindrical and elliptical coandă aircraft design

Small aerial vehicles possess advantages in terms of size and accessibility in performing a variety of tasks. Presently, their design and performance is dependent on variations of conventional aerodynamic configurations (fixed- and rotary-wing). A disadvantage for these configurations is the aerodynamic potential between the mainstream airflow and the body surfaces are not fully utilized. To solve this issue, the Coandă effect is proposed whereby a high-velocity jet is blown tangentially over a curved surface to increase circulation and lift. Prior to the costly approach (experimental and numerical), an analytical formulation (via control volume analysis) to predict the aer-odynamic Coandă lift force of the design concept is developed. This is an extended version of the existing mathematical formulations, capturing viscous flow effects. It is also pertinent for circular and elliptical-shaped designs. The results obtained show that the total lift force is dependent on the jet velocity, outflow angle, dimensions of the jet slot, the projected surface area, and the viscous effect. The approach has demonstrated how this modelling technique is effective in calculating the lift force for cylindrical and elliptical Coandă aircraft design

Islamic Educational System in Kelantan, Malaysia: Traditional and Modern Approaches

Abstract: Islamic Education in Malaysia began as an informal institution in its early days. This is because of the nature of development during those times, where some places such as surau, mosque and madrasah became centre for teaching the aspects of the religion. The system develops gradually, from informal to a formal system which has changed the style of learning. Nevertheless, the informal system is still existed even until today, along with the formal educational system. This is especially in Kelantan, where it becomes clear that both institutions are still running concurrently. In this paper, the authors aim to examine and analyse the Islamic Educational system in Kelantan as it is a unique experience for such a state to keep traditional institution running in this day. This paper will also discuss the development of the formal system that is established for educating the religion to the people