Improving airfoil aerodynamic performance is an essential aspect of aerodynamic technology. The use of passive flow control is one way to enhance the aerodynamic performance of the airfoil. The influence of using gurney flaps as passive flow control was explored through the CFD approach employing the RANS control equations with the k-epsilon turbulence model. The airfoil model utilized in this investigation was the NACA 4415 operating at a Reynolds number of 1×106. This study explored three different variations of flap height, namely 0.5%, 1%, and 2% of chord length. The outcomes showed that adding gurney flaps showed quite positive results in increasing the lift and drag performance of NACA 4415. An airfoil with a 0.5%c height flap has an average percentage increase in Cl of 12%, followed by a height flap of 1%c, which is 23%, and a percentage Cl of 37% for a height flap of 2%c. Meanwhile, each variation in height flap affected the increase in Cd. A height flap of 0.5%c increased Cd with an average percentage of 2%, while a height flap of 1%c increased the percentage of Cd by 4% and 6% for a height flap of 2%c. Moreover, visualization of fluid flow with pressure and velocity contours given at AoA 12º to determine the effect on the increase in Cland Cd in NACA 4415.

Airfoil that experiences erosion caused by flying debris that hit the airfoil can affect the performance of the airfoil. This research was studied to determine the effect of erosion with varying erosion length using numerical methods on the performance of the NACA 0015 airfoil. This research was simulated using the Computational Fluid Dynamics (CFD) approach. Reynolds Averaged Navier-Stokes (RANS) is implemented as the governing equation. The turbulence model used in this research is the k-epsilon model. The Reynolds number used is 1.5 x 10⁶. This research proves that the erosion effect can reduce the Cl value and increase the Cd value on the NACA 0015 airfoil. Increasing the erosion length on the airfoil can also affect the Cl value and Cd value, but this effect is insignificant. In the contour visualization, it can be seen that the airfoil that is experiencing erosion has a pressure contour that increases in the upper chamber and decreases in the lower chamber compared to the airfoil that does not experience erosion so that it can reduce the lifting force of the NACA 0015 airfoil. The flow velocity and streamline contours also show greater circulation in the erosion airfoil, which can accelerate the stall by 1o AoA. Then, variations in increasing erosion length on the airfoil do not show any significant differences in pressure contours or circulating flow.

This study investigates the effect of variations in the micro geometry with various forms as passive flow control devices on the aerodynamic capability of the airfoil. Micro-cylinder, micro-slat, and micro-cube are installed close to the leading edge of the NACA 4415 airfoil as a micro geometric variation of passive flow control devices with a predetermined diameter of 3% c located at coordinates x= 0% c and y= 8 %c of the leading edge of the airfoil. The Reynolds number used in this study is Re = with AoA variations from 0°-30°. This study's results show a decrease in Cl of 12% with a micro-cylinder, 26% with a micro-slat, and 28% with a micro-cube. In addition, the Cd produced by using the variation of the device micro geometry has increased significantly. Thus, the final result is a lift-to-drag ratio of more petite than the without micro. In the streamlined contour shown when the airfoil is at a high angle of attack, the use of micro geometric variations of passive flow control devices can have an effect that causes reduced recirculation that occurs in the airfoil. However, the impact of these devices is not optimal, resulting in a reduction in the aerodynamic capability of the NACA 4415 airfoil.

This study uses a numerical method to analyze the cavity's use on the airfoil's trailing edge and the aerodynamic effects it generates. The type of airfoil used is NACA 4415. The variations in the Reynolds number examined in this study are 2×105 and 3×105. The governing equation is the Reynolds Averaged Navier-Stokes paired with the k-ε turbulence model. This study concludes that the cavity can increase Cl in the airfoil but cannot delay the stall. The increase in Cd is also a negative effect of using a cavity in the airfoil. The cavity can increase Cl by increasing the pressure on the lower side near the trailing edge. Meanwhile, the cavity increases Cd because it creates a separation of the fluid flow, forming a vortex when viewed in a streamlined form of fluid flow.

This study was conducted using the Computational Fluid Dynamics (CFD) method using the Reynolds Averaged Navier Stokes (RANS) approach. The type of airfoil used in this study is the asymmetry NACA 4415 airfoil type. In this paper, computational tests were carried out on the airfoil with the addition of bionic flaps on its trailing edge. This study's update tests three variations of the Reynolds number: Re = 106, Re = 5 × 105, and Re = 3 × 105. The airfoil test was carried out at AoA 0°–25°. The addition of bionic flaps causes a decrease in lift performance at low AoA, but at high AoA, it can increase lift performance on airfoils. In addition, adding a bionic flap on the airfoil can delay the occurrence of a stall. At AoA 10°–13°, the Cd of the three variations of the Reynolds number experiences an increase in performance. Then, from this computational test, the resulting Coefficient moment (Cm) is a pitch down because the torque is below zero.

Indonesia is the world’s main exporter of patchouli plants (Pogostemon Cablin Benth). Patchouli plants produce essential oil by distillation; this essential oil has a constituent component called patchouli alcohol and is widely used in the aromatic industry. Therefore, a patchouli refining process is needed so that Indonesia’s patchouli can improve its quality in the eyes of the world. The purpose of this research is to observe the process of cooling hot patchouli steam into patchouli oil to optimize the current process. This study's analytical method is a simulation approach with CFD software. 50 kg of dried patchouli leaves and stems will go through a combustion process and then be distilled in a 150 liter volume tank for 5 hours. During the distillation process, there is a heat transfer phenomenon called conduction and convection. The LMTD value was 327 K, the heat transfer rate was 103,39 W, the overall heat transfer was 223,45 W/m2K, the NTU value was 0,018, and the system's effectiveness was 0.89% using LMTD and the -NTU method.

The computational study discusses the application of the co-flow jet technique as a fluid flow control device on the NACA 0015 airfoil. The numerical equation used is the RANS equation with the k-ε turbulence model. There are three variations of the mesh proposed in this paper. The first variation is a fine mesh with 100,000 elements. The second variation is a medium mesh with 50,000 elements. Meanwhile, the third variation is coarse mesh with 25,000 elements. Based on the mesh independence test results, the mesh with the lowest error value is the fine mesh. Co-flow jet is proven to control fluid flow on the upper side of NACA 0015. Co-flow jet can also improve the aerodynamic performance of NACA 0015 by increasing Cl and decreasing Cd. The increase in Cl was 114% and the decrease in Cd was 24%. The fluid flow separation on the upper side of the airfoil can also be handled well by the co-flow jet.

Issues in friction stir spot welding focus mainly on the mechanical characteristic affected by its Hardness. This Hardness must be maintained by evenly temperature distribution in weld zones during welding. The process parameters are mainly responsible for the development of the hardness of the friction stir spot weld. This study presented the hardness evaluations on the friction stir spot weld via the Hardness-Vickers test and analysis of the temperature distribution in the weld zones via the finite element method. The workpiece samples used in this study were Aluminium alloy 5052-H112 with a thickness of 2 millimeters in the lap-shear mode based on 3 main parameters at low and high levels of parameters configuration. The results obtained via the Hardness-Vickers tests exhibited a value of 42-HV located in the middle of the spot-weld center using a low-level parameters configuration. This value increased to 64-HV around the vicinity of the keyhole. And then the value decreased to 53-HV outside the keyhole, about 6 millimeters from the spot-weld center. Using high-level parameter configuration, the Hardness-Vickers value increased to 61-HV in the middle of the spot-weld center. The value then increased to 76-HV in the vicinity of the keyhole. Furthermore, the value decreased at 60-HV outside the keyhole, which ca 6 millimeters away from the spot-weld center. The temperature distribution of the weld zones achieved 480 oC in the vicinity of the keyhole using the low-level parameter configuration. Slowly, the temperature declined to 380 oC at 6 mm away from the friction spot-weld center in the HAZ. Using the high-level parameters configuration, the temperature distribution reached 540 oC in SZ, and slowly reduced to 425 oC in HAZ. Based on the results, it was found that by using high-level parameters configuration the hardness of the friction stirs spot weld exhibited better Hardness-Vickers value and evenly temperature distribution in the weld zones.

In the current technological development, the electric motor is the most popular in various industrial applications. Electric motors today have evolved very quickly and have a significant impact on the lives of the wider community. The use of environmentally friendly and efficient energy is one of the reasons why this motorbike has become a pioneer of technological advances, especially in the automotive world. This research focuses on conducting a comprehensive analytical study on one type of electric motor, namely synchronous because it is widely applied in various conditions today. The analysis was carried out using a computational method by applying the finite element as a method of solving the magnetic field case involving Maxwell's equations and its impact on the torque generated in this synchronous motor. From the computation results, it is found that this synchronous motor does have a high torque when the magnetic field flux works constantly at 0.015 Wb. With an average torque generated by this synchronous motor of 1.5 kW.

Penggunaan biosolar B20 dalam pemanfaatan energi diesel di Indonesia terus dikembangkan. Dalam dunia industri, regulasi pemerintah mewajibkan untuk menggunakan bahan bakar jenis diesel tanpa terkecuali. Bahan bakar tersebut sebagai energi terbarukan sehingga mengurangi penggunaan bahan bakar fosil. Pada kuartal III tahun 2018, diluncurkan regulasi biosolar B20 untuk semua industri. Kecemasan pelaku industri karena pengalihan bahan bakar dari solar menjadi biosolar B20 dari segi performa mesin inilah sehingga dilakukan penelitian ini untuk menjawab pertanyaan pelaku industri. Metode yang digunakan adalah metode eksperimental dengan menggunakan bahan bakar solar dan biosolar B20 terhadap mesin uji berbahan bakar diesel. Dari semua putaran yang telah diuji didapatkan bahwa bahan bakar jenis solar mempunyai kebutuhan bahan bakar spesifik paling ekonomis ketika putaran mesin 2100 rpm dengan nilai 0,064 l/kWh dan tenaga 230,23 HP. Torsi maksimal dicapai ketika putaran 1000 rpm pembebanan 100% dengan nilai 1575 Nm pada bahan bakar jenis solar. Daya teoritis maksimum dihasilkan oleh bahan bakar jenis solar pada putaran mesin 2100 rpm kondisi high idle dengan nilai 235,12 HP. Daya efektif mesin maksimum juga dihasilkan oleh bahan bakar jenis solar pada putaran mesin 2100 rpm kondisi high idle dengan nilai 235,33 HP.

Mobil adalah salah satu alat transportasi yang sangat diminati oleh masyarakat Indonesia. Dalammemnuhi harapan masyarakat akan sebuah mobil, pihak pabrikan biasanya terus berlomba dalampengembangan teknologinya salah satunya dalam teknologi pengembangan mesin. Saat ini teknologi mesinyang terus berkembang adalah bagaimana bisa menghasilkan tenaga mesin yang besar namun tetap irit bahanbakar. Salah satu teknologi tersebut yang ada saat ini adalah Variable Valve Timming with Intelligence (VVTI) yang sudah terkenal. Saat ini teknologi ini pun terus dikembangkan menjadi Dual VVT-I dengan keunggulan lebih bertenaga dan irit bahan bakar. Dalam penelitian ini akan dilakukan pengujian menggunakan metode eksperimental langsung untuk menguji performa tenaga mesin yang dihasilkan dari dua generasi mesin tersebut menggunakanalat mesin Dyno Test dimana 2 mobil yang memiliki perbedan mesin tersebut di test running sampai menyentuh limitnya sehingga dapat diukur hasil tenaga yang dihasilkan secara real on wheel dan didapat terjadi perbedaan sampai 3 Horse Power antara dua mesin tersebut dengan Dual VVT-I yang lebihtinggi.

Flow separation is a phenomenon that greatly affects the airfoil performance due to adverse pressure gradient. The loss in kinetic energy behind the separated flow region causes undesirable effects, contributing greatly to the increased drag force. In order to overcome this condition, one of the alternative methods is to provide momentum into the fluid in order to counter the adverse pressure gradient thus eliminating the flow separation. This paper discusses the use of plasma actuator located at 0.21 c from leading edge of an airfoil NACA 4415. The investigated areas are the ones of Reynolds numbers 35,000, 100,000, and 200,000. This study uses experimental method. Load cells have been used to obtain aerodynamic force thus the data have been validated from computational methods. In addition, there is also flow visualization in order to understand the flow phenomenon through the testing model. The results of this experimental study show that plasma actuator can increase the value of lift coefficient (CL) and decreasing drag coefficient with the average increase of CL is 24.90%, 7.81% and 1.37%, and also the average decrease is CD is 8.45%, 0.86% and 1.96% in each variation of Reynolds number. The best result is found at Re 35,000 and it is adequate to produce the best separation delay point of 0.0107 c at α = 9°.

Mesin gerinda copy camshaft adalah mesin untuk menduplikat atau memperbanyak camshaft. Tujuan dari rancang bangun ini adalah agar pengerjaan pembuatan camshaft menjadi lebih mudah karena mesin melakukan copy master secara otomatis sesuai dengan master tersebut. Metode perancangan yang digunakan adalah metode Ulrich & Eppinger serta metode DFMA sebagai metode manufakturnya. Proses racang bangun mesin gerinda copy camshaft ini meliputi:pembuatan konsep desain, identifikasi bahan, identifikasi mesin dan peralatan yang digunakan, serta identifikasi gambar kerja. Hal yang perlu di perhatikan dalam pembuatan mesin gerinda copy camshaft ini adalah kerapatan sambungan pada rangka atas dan kaki rangka sehingga tidak terjadi getaran pada saat mesin beroperasi. Mesin ini memiliki dimensi panjang 1000 mm, lebar 600 mm, tinggi 500 mm. Pengujian kinerja mesin yang dilakukan dengan cara pengujian secaralangsung membuat camshaft. Hasil pengujian waktu yang dibutukan untuk membuat satu buah camshaft adalah 10 menit, dengan kecepatan putaran 2800 RPM.

Various studies have been conducted regarding the heat problem of Libya’s building recently. The current method is to create a heat barrier in all parts of the building. Thermal insulation R-value of each material and the heat transfer coefficient such as U-value confirms to the Egyptian standards. This research was conducted by using a new design of double wall heat insulation materials which are available in Libya. This new design is to be compared to previous research. The proposed double wall and generated R-value provide higher efficiency than the best efficiency ever done.

Turbocharger merupakan suatu komponen yang digunakan pada kendaraan bermotor untuk meningkatkan daya dari motor dengan melakukan penambahan rapat massa udara yang lebih banyak dibandingkan dengan cara pengisian biasa. Turbocharger memanfaatkan tekanan gas buang untuk memutar turbin yang kemudian menghasilkan energi untuk memutar kompressor yang berfungsi untuk membantu memasukan udara ke dalam ruang bakar. Dengan memasang perangkat tersebut, diharapkan daya dari motor akan meningkat dan lebih efisien. Analisis ini bertujuan untuk mengetahui, meneliti, dan menganalisis daya dan efisiensi thermal yang terjadi pada mesin bensin 4 langkah Mercedes Benz C200 dengan teknologi turbocharger. Dari hasil analisis ini, dapat diketahui peningkatan nilai daya dan efisiensi thermal yang dihasilkan oleh mesin bensin 4 langkah Mercedes Benz C200 dengan teknologi turbocharger.

Pada sebuah instalasi Pompa sebagai Turbin (Pump as Turbine)(PAT), impeller merupakan salah satu komponen utama dalam peningkatan jumlah energi listrik yang dihasilkan. Hasil penelitian sebelumnya menunjukan bahwa impeller dengan kekasaran permukaan yang lebih halus akan menghasilkan energi yang besar. Impeller biasanya terbuat dari besi, baja, perunggu, kuningan, aluminium, plastik atau material non korosif lainnya. Terdapat beberapa metode pembuatan impeller, diantaranya adalah proses permesinan dan proses pengecoran. Berbagai metode sudah dikembangkan untuk mendapatkan produk pengecoran yang lebih baik dari yang sudah ada salah satunya pengecoran menggunakan investment casting. Pembuatan impeller dengan metode investment casting mampu menghasilkan produk tanpa memerlukan proses permesinan lebih lanjut.Secara teoritis, prosedur pengecoran dengan metode investment casting meliputi pembuatan pola (material pola diinjeksi kedalam cetakan), setalah material pola (wax) mengeras dikeluarkan dari cetakan dengan dipanaskan. Kemudian pola dicelupkan kedalam adonan bubur ceramic slurry, lalu pola di stucco diberi taburan partikel-partikel keramik kasar. Ditunggu sampai mengeras hingga menjadi cetakan keramik. Setelah mengeras cetakan keramik dipanaskan untuk mengurangi kadar air pada cetakan. Namun pada penelitian ini, akan dilakukan modifikasi pembuatan pola yang biasanya menggunakan wax, diganti oleh pola 3D Printing berbahan PLA 1,75 mm. Berdasarkan pengukuran kualitas impeller diketahui bahwa impeller yang dihasilkan memiliki diameter luar 130 mm, kekasaran permukaan dalam 23,08 𝜇𝑚 dan luar 0,47 𝜇𝑚, dengan kekerasan rata-rata 85,4 HRB. Dari hasil perbandingan kualitas impeller hasil pengecoran terhadap impeller original diketahui bahwa kekasaran permukaan impeller produk investment casting lebih baik 61% pada permukaan luar dan 22,1% pada permukaan dalam serta 20,28% lebih baik tingkat kekerasannya dibandingkan impeller aslinya.