Performance Improvement of a Supercritical Airfoil by a Multi-point Optimized Shock Control Channel

2017 ◽  
Vol 100 (3) ◽  
pp. 675-703
Author(s):  
A. Nejati ◽  
K. Mazaheri
2014 ◽  
Vol 1 (1) ◽  
pp. 215-220
Author(s):  
A Saeed ◽  
Malik. S. Raza ◽  
Ahmed Mohsin Khalil

AbstractAir travelling is the second largest travelling medium used by people. In future it is expected to be the first choice for the travellers. As increase in the price of oil cost of air travelling is getting higher. Engineers are forced to find the cheaper means of travelling by innovating new techniques. This paper presents the new idea to reduce air travelling cost by reducing drag, which is major driving factor of high fuel consumption. Two-dimensional and three-dimensional shock control contour bumps have been designed and analysed for a supercritical wing section with the aim of transonic wave drag reduction. A supercritical airfoil (NACA SC (02)-0714) has been selected for this study considering the fact that most modern jet transport aircraft that operate in the transonic flow regime (cruise at transonic speeds) employ supercritical airfoil sections. It is to be noted that a decrease in the transonic wave drag without loss in lift would result in an increased lift to drag ratio, which being a key range parameter could potentially increase both the range and endurance of the aircraft. The major geometric bump parameters such as length, height, crest and span have been altered for both the two-dimensional and three-dimensional bumps in order to obtain the optimum location and shape of the bump. Once an optimum standalone three-dimensional bump has been acquired an array of bumps has been manually placed spanwise of an unswept supercritical wing and analysed under fully turbulent flow conditions. Different configurations have been tested with varying three-dimensional bump spacing in order to determine the contribution of bump spacing on overall performance. The results show a 14 percent drag reduction and a consequent 16 percent lift to drag ratio rise at the design Mach number for the optimum arrangement of bumps along the wing span. This innovative technique proves to be a bridge between economical problems and engineering solutions and a milestone for aviation engineering.


2017 ◽  
Vol 24 (1) ◽  
pp. 274-292 ◽  
Author(s):  
Karim Mazaheri ◽  
Ashkan Nejati ◽  
Kiarash Charlang Kiani

2011 ◽  
Vol 54 (11) ◽  
pp. 2935-2944 ◽  
Author(s):  
Yun Tian ◽  
PeiQing Liu ◽  
PeiHua Feng

2020 ◽  
Vol 1 (3) ◽  
pp. 316-324
Author(s):  
Syukrani Kadir

periodically in preparing learning plans, implementing learning, assessing learning achievement, carrying out follow-up assessments of student learning achievement that can improve teacher performance. This performance improvement is through periodic collaborative educational supervision. Based on the results of educational supervision in cycle I and cycle II, teacher performance increased, namely in cycle I, teacher performance in preparing learning plans in cycle I reached 71.98%, while cycle II was 92.44%. Teacher performance in implementing learning cycle I reached 72.44% while cycle II reached 93.81%. Teacher performance in assessing learning achievement in cycle Im reached 81.30% while cycle II was 90.56%. Teacher performance in carrying out follow-up assessments of student learning achievement in the first cycle reached 59.76% while the second cycle was 83.00%. Thus, the average action cycle II was above 75.00%. Based on the results of this study, it can be concluded that the teacher's performance has increased in preparing learning plans, implementing learning, assessing learning achievement, carrying out follow-up assessments of student learning achievement.


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