Drag aerodinamika pada kendaraan disebabkan adanya tekanan rendah dan separasi aliran di bagian belakang, yang berdampak pada menurunnya kecepatan, meningkatnya penggunaan bahan bakar, dan turunnya efisiensi kendaraan. Blowing merupakan salah satu pilihan rekayasa kendali aktif aliran yang dapat diterapkan pada desain kendaraan yang dapat mengendalikan pembentukan separasi aliran dan berefek positif berupa pengurangan hambatan aerodinamis. Penelitian ini bertujuan menganalisis pengaruh penerapan blowing terhadap pola aliran, distribusi tekanan, dan hambatan aerodinamika yang bekerja pada bagian belakang model. Dengan bantuan CFD Fluent 6.3, model uji yang digunakan adalah model kendaraan dengan sudut kemiringan geometri depan (α) 35o dan rasio terhadap model Ahmed bodi original adalah 0.17 (1:6), yang dilengkapi dengan blowing dengan kecepatan 1.0 m/s. Hasil komputasi mengindikasikan bahwa penerapan blowing dapat mengurangi pembentukan wake dan menunda separasi aliran dan dapat meningkatkan koefisien tekanan minimum pada bagian belakang model kendaraan sebesar 24.690%. Pengurangan hambatan aerodinamika diperoleh sebesar 9.583%.
The innovation in the automotive industry must prioritize the issue of energy security and the environment. One aspect of the innovations is regarding the development of more aerodynamic vehicle design. The study of vehicle aerodynamics has been considered as very important, due to its direct relation to the safety and efficiency factors of energy utilization. Applying active control on the onset region of flow separation is one example of the efforts. This study aims to analyse the effect of the application of active control by suction to the aerodynamic drag of the vehicle model through qualitatively observations of flow dynamics and quantitatively pressure fields. The test model is a modified Ahmed body with 35° slant angles and varied flow orientations. This study has been conducted in both numerical computation and experimental testing at a suction velocity of 1.0 m/s and upstream velocity of 11.1 m/s, 13.9 m/s, and 16.7 m/s, respectively. The results have found out that the attachment of active control is proven capable able to delay flow separations, to increase the pressure coefficients on the back wall, and to reduce aerodynamic drag by 10.8487% for computational methods and 10.9748% for experimental methods.
The production of the crude oil in Indonesia is slowly deceasing by the year, while the consumption of the fuel is still increasing. The matter being comparable within its consumtion is that it makes Indonesia keep impoerting the fuel in order to fulfill its need in every year. It is because there is no new invention of the new oil-mill. Thus, a new penetration to provide an alternative fuel to press the consumption level is needed. Ethanol however, is one of the newest alternative fuels which can be used as the additional substance of the use of the fossil fuel. Ethanol contains of up to 35% oxygen so that it will produce the perfect combustion even if it is in small unit of substance. The aim of this research was to find out the effect of the use of the mixture of the ethanol-pertalite toward the fuel combustion. The research was using the Honda Scoopy 110 cc motorcycle with 1 cylinder injection system. The liquid tank is designed by using plastic container so that it will be possible to be detached and paired to make the consumtion measuring easier. The test vehicle was operated above chasis dynamometer. Engine scanner, especially for Honda was used to sett the rpm, finding out the throotle position, ignition timing, oxygen sensor and the ratio of water fuel. The result of the research was showing that the use of the mixture fuel E-40 is the best mixture, in which E-40 usage is 14,3% more frugal rather that the combustion of the pure pertalite.
Abstrak: Kajian Komputasi dan Eksperimental Pengaruh Kontrol Aktif terhadap HambatanAerodinamika Model Kendaraan. Dinamika aliran udara sangat dipengaruhi oleh pembentukan separasi di sekitar bodi kendaraan. Separasi aliran menjadi pemicu perbedaan tekanan yang signifikan antara sisi depan dan belakang sehingga muncul efek tarikan ke arah belakang sebagai kontributor utama besarnya hambatan aerodinamika yang diterima kendaraan. Penelitian ini fokus pada kajian hambatan aerodinamika dengan memperhatikan karakteristik pola aliran yang terbentuk dan distribusi tekanan pada dinding belakang model kendaraan melalui metode simulasi komputasi dan eksperimental laboratorium. Kontrol aktif tiupan ditempatkan pada sisi atas dinding belakang Ahmed model dan diatur pada kecepatan 1.5 m/s. Hasilnya menunjukkan bahwa penggunaan kontrol aktif tiupan pada sisi belakang mampu menunda separasi, meningkatkan koefisien tekanan, dan mengurangi hambatan aerodinamika model kendaraan.
Abstract: Computational and Experimental Studies of the Effect of Active Control on Aerodynamic Drag of Vehicle Models. The dynamics of air flow is strongly influenced by the formation of separations around the vehicle body. The flow separation triggers a significant pressure difference between the front and rear sides so that a rearward pull effect appears as the main contributor to the amount of aerodynamic drag received by the vehicle. This research focuses on the study of aerodynamic resistance by paying attention to the characteristics of the flow pattern formed and the pressure distribution on the rear wall of the vehicle model through computational simulation methods and laboratory experiments. The blowing active control is located on the upper side of the back wall of the Ahmed model and is set at a speed of 1.5 m/s. The results show that the use of blowing active control on the rear side is able to delay separation, increase the pressure coefficient, and reduce the aerodynamic drag of the vehicle model.
As the air flow reaches the rear part of the vehicle the flow will undergo separation generated by friction and fluid viscosity, and creating wake, considerably large turbulent area with low pressure at the rear of the vehicle which results in pressure drag which can reduce vehicle performance. The research was carried out with a computational and experimental approach. The test model used in this study is a model of a family van model which is a modification of the Ahmed body model. The rear part of the vehicle model is equipped with an active control feature in the form of a suction with a slant angle (α) of 35 . The upstream speed and suction speed are 11.1 m/s and 0.5 m/s, respectively. The results obtained indicate that the application of active suction control is able to reduce wake formation and delay flow separation compared to the uncontrolled model, and is able to increase the minimum pressure coefficient on the rear wall of the vehicle model with an increase of 41.49%, and is able to reduce the drag coefficient by 11.0260% for the approach. computation and 11.0080% for the experimental approach.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.