The research is conducted in order to reduce energy losses caused by the secondary flow in the endwall junction. This phenomenon is caused by the interaction of two adjacent viscous flow (symmetric airfoil and endwall). Reduction of energy loss carried out by addition of Foward Facing Step Turbulator (FFST) in the upstream. Endwall junction area is modeled as a NACA 0015 airfoil and a flat plate. Position of FFST is at a distance L = 2/3 C upstream leading edge and a thickness d = 4% C. Free stream conditions Red = 105 with turbulence intensity (Tu) 5%. Research is conducted by numerical and experiment methods. Pathlines of numerical result methods has an identic structure with "Oil Flow Visualization" of the experiment.Result of the research states that the addition of FFST can increase the turbulence intensity in the flow near the wall. So at the same angle of attact (α), the saddle point position on the leading edge has distance nearly the same but a little more towards the lower side and the separation line is wider than without FFST. Because the flow has stronger turbulence intensity, attachment line of the upper and lower sides have a better capability of following the contours of the body. So the point of separation can be delayed and blockage (energy loss) can be reduced as well. Reduction of energy loss is most effective on α=8 ° (4.16%),Keyword : Secondary flow, forward facing step, turbulent intensity.

1 AbstractThe flow characteristic around two circular cylinders in tandem arrangement located near a plane wall were investigated experimentally in a uniform flow at a Reynolds Number of 5.3 x 10 4 . The center to center spacing between the two cylinders relative to the cylinder diameter was constantly maintained at P/D = 1.5. The pressure distributions along the surface of the cylinder and the plane wall were measured by varying the gap-to-diameter of cylinder ratio (G/D) in the range of 0 < G/D < 0.467. Surface oil-film techniques were used to investigate the flow patterns on the cylinder. The result showed that for upstream cylinder, in the gap-to-diameter ratio G/D < /D, there is no stagnation point at front side of the upstream cylinder; it is gradually raised as the gap increase. For the downstream cylinder, a peak on the lower side of the front side of the cylinder is apparent in each of the pressure distributions. This peak represents the reattachment of shear layer that separates from lower side of the upstream cylinder. The reattachment point tends to move forward close to the angular position of  = 0 o as the gap ratio increase. The shear layer bifurcates into two shear layers. One shear layer continues in the downstream direction, and the other shear layer flows in the upstream direction.Keywordscircular cylinders, gap-to-diameter of cylinder ratio, plane wall, tandem arrangement AbstrakDalam penelitian ini telah diamati secara eksperimen karakteristik aliran melintasi silinder ganda yang tersusun secara tandem di dekat dinding datar, untuk aliran seragam (uniform flow) dengan bilangan Reynolds, Re = 5,3 x 10 4 . Untuk jarak antar titik pusat kedua silinder ditetapkan konstan sebesar P/D = 1,5, distribusi tekanan sepanjang permukaan kedua silinder dan dinding datar diukur dengan memvariasikan rasio antara gap dinding dengan silinder dan diameter silinder (G/D) dalam rentang 0 < G/D < 0,467. Metode surface oil-film digunakan untuk memvisualisasikan bentuk aliran pada silinder. Hasil eksperimental menunjukan bila rasio jarak gap G/D < rasio antara tebal lapis batas dan diameter (/D) tidak terjadi titik stagnasi di bagian depan dari silinder upstream; namun stagnasi berangsur-angsur muncul sejalan dengan meningkatnya jarak gap. Sedangkan untuk silinder downstream, pada setiap distribusi tekanan yang diukur terdapat puncak tekanan pada sisi bawah dari bagian depan silinder. Puncak ini menunjukkan posisi reattachment dari shear layer yang terseparasi dari bagian bawah silinder upstream. Sejalan dengan meningkatnya rasio gap, titik reattachment cenderung bergerak maju mendekati posisi  = 0 o . Shear layer terbagi menjadi dua di mana salah satu shear layer menuju ke arah downstream sedangkan shear layer yang lain menuju ke arah upstream.Kata Kuncisilinder sirkular, rasio gap antara dinding dengan silinder, dinding datar, susunan tandem

An impulse turbine uses drag force on its blades to produce torque on its rotor. As fluid flows over the blades, pressure changes occur at the nozzle, which increases the fluid's velocity and reduces the static pressure at the nozzle outlet. The high-momentum fluid then impinges on the rotor blades, generating frictional force and resulting in torque production. To study the impact of blade shape and number on the turbine's performance, simulations were conducted. The results indicate that blades with an angle of 0° and 180° are optimal for creating high-pressure vortices on the concave surface of the blade. Addition-ally, more blades always result in higher torque and power out-put by increasing the active area of the blades. However, in the case of blades with an angle of 0° and 180°, 8 blades produced more torque than 12 blades with an angle of 0° and 90°. There-fore, blades with an angle of 0° and 180° are highly effective at generating drag force and producing torque.

Flow and thermal field of a parallel flow vortex tube has been simulated and analyzed numerically. A secondary zone model is found at the core region near the inlet to the middle of the vortex tube. Blockage effect due to a narrow area of the hot exit has deflected air flow towards the cold exit, caused expansion and compression at the cold and hot outlet, respectively. The cooling and heating effect due to energy separation is contributed by expansion and compression of air near the outlet. Coeficient of performance (COP) for a refrigerator is higher as cold mass fraction increases due to a higher temperature difference and cold mass flow rate

Undang-Undang Nomor 33 Tahun 2014 Tentang Jaminan Produk Halal telah berjalan. Namun sejumlah kebijakan dari produk hukum tersebut masih belum tersosialisasikan dengan baik, terutama bagi kalangan pelaku usaha di sektor makanan dan minuman UMKM. Begitu juga yang terjadi pada sebagian penggiat UMKM di Kabupaten Madiun yang belum tahu menahu mengenai kebijakan tersebut. Mereka kurang kesadaran bahwa mengurus perizinan dan sertifikasi halal terhadap produk mereka adalah suatu hal yang sangat penting dan tentunya akan memberikan banyak manfaat bagi keberlangsungan usaha mereka. Permasalahan muncul tidak hanya dari sisi sosialisasi kebijakan, namun juga dari sisi literasi pelaku UMKM dalam hal proses produksi halal yang masih rendah. Dari permasalahan tersebut, penulis mengusulkan solusi dalam bentuk sosialisasi, pembinaan, dan pendampingan kepada UMKM di Madiun terkait proses produksi halal dan sertifikasi halal. Dengan demikian, program-program tersebut diharapkan dapat membantu UMKM khususnya di Kabupaten Madiun untuk mendapatkan sertifikat halal bagi produknya sehingga mampu memberikan nilai tambah dan secara tidak langsung ikut mendukung berlangsungnya kebijakan jaminan produk halal.