Hasil Pencarian  ::  Simpan CSV :: Kembali

Abstrak :
Water tunnel merupakan salah satu alat yang digunakan untuk melakukan penelitian mengenai fenomena-fenomena dinamika fluida. Salah satu keunggulan dari water tunnel adalah dapat menampilkan visualisasi aliran yang lebih jelas. Water tunnel ini merupakan alat praktikum di Departemen Teknik Mesin Universitas Indonesia. Untuk mempelajari bermacam-macam fenomena mekanika fluida yang terjadi, kita harus memiliki berbagai macam profil benda uji/spesimen yang akan diamati. Untuk itu dibuatlah perangkat alat yang dapat memegang benda uji tersebut secara stabil dan kuat, serta dapat mengakomodasi berbagai bentuk profil yang hendak diamati serta pergerakan atau posisinya. Pemegang benda uji/spesimen ini dapat beroperasi didalam air, dapat mengerakan spesimen maju-mundur sebesar 250[mm] dengan kelipatan 50[mm], dapat mengerakkan spesimen naik-turun sebesar 50[mm],dan dapat mengakomodasi pergerakan berputar spesimen pada titik beratnya. Dengan bekerja sama dengan saudara robert, menggunakan metode visualisasi aliran yaitu dye injection untuk melihat visualisasi aliran yang terjadi. Karakteristik force balance yaitu drag force untuk prototype silinder berdiameter 1,5? didapatkan, dengan mengunakan beberapa asumsi untuk mendapatkan tekanan pada permukaan silinder. ......Water tunnel is one of research tool for studying about fluid dynamic phenomenon. One of the advantages of using water tunnel is its can give better flow visualization. This water tunnel is an experimental tool for Mechanical Engineering Department, University of Indonesia. To studying all kind of fluid dynamic that occurring, we must provide several profile specimen which can be observed. For that constructed model support system which able to hold the specimen stable and strong, and also able to accommodate any profile we want to observe including its movement and positioning. The model support system able to operate under water, its can move specimen forward and backward for 250[mm] for every 50[mm], its can move specimen up and down for 50[mm], and its can accommodate specimen revolution on its weight point. By cooperate with Robert; using flow visualization method is dye injection to observe flow visualization that occurred. Force balanced characteristic which is drag force for prototype cylinder with diameter 1.5? is occupied, by using few assumption to get pressure at cylinder surface.

Abstrak :
Bagian sayap depan mobil adalah salah satu elemen aerodinamis yang memberikan dampak signifikan karena pengaruhnya terhadap aliran udara di seluruh bagian badan mobil karena sayap depan mobil merupakan bagian pertama yang bersentuhan dengan udara. Sayap depan mobil juga memengaruhi aliran udara pada saluran rem, radiator dan diffuser, dan main engine intake. Lokasinya sebagai elemen aerodinamis yang terkena fluida terlebih dahulu menjadi sangat penting karena produksi downforce oleh sayap depan juga akan memberikan dampakdampak lain kepada komponen lain sampai di belakang. Dengan dasar ini, penulis ingin melihat perkembangan aspek aerodinamis yang dipengaruhi oleh sayap depan pada tahun 2018 dan 2019. Penelitian ini dibantu oleh perangkat luna berupa auto desk inventor untuk mendesain sayap depan dan CFD untuk menyimulasikan sisi aerodinamis pada sayap depan yang telah didesain. Berdasarkan hasil analisis yang telah dibuat oleh penulis, dapat disimpulkan bahwa desain sayap depan tahun 2019 berhasil memberikan down force yang lebih besar dibandingkan dengan sayap depan tahun 2018 sebesar 35%, down coefficient sebesar 10%, penurunan drag coefficient sebesar 4%, dengan adanya kenaikan pada nilai drag force sebesar 16% pada bagian sayap depan. Hal ini dikarenakan bentuk sayap depan 2018 memiliki cascade yang mengarahkan fluida untuk menjauh dari ban dengan tujuan mengurangi drag force. ......The front wing of the car is the only aerodynamic element that has a significant impact because of its effect on air flow throughout the body of the car and because the front wing of the car is the first part that comes into contact with air. The front wing of the car also affects the air flow in the brake lines, radiator and diffuser, and the main engine intake. Its location as an aerodynamic element that is exposed to the fluid first becomes very important because the production of downforce by the front wing will also have other impacts on other components downstream. With this basis, the author wants to see the development of aerodynamic aspects that are influenced by the front wing in 2018 and 2019. This research is assisted by a software tool in the form of an auto desk inventor to design the front wing and CFD to simulate the aerodynamic side of the designed front wing. Based on the results of the analysis made by the author, it can be concluded that the front wing design in 2019 succeeded in providing a down force greater than the 2018 front wing by 35%, down coefficient by 10%, decrease in drag coefficient by 4%, with an increase at a drag force value of 16% on the front wing. This is because the shape of the front wing 2018 has a cascade that directs the fluid to move away from the tire in order to reduce drag force.

Abstrak :
This paper provides an explanation of the effects of cavity shape and frequency excitation to the vortex formation of the synthetic jet. In order to get comprehensive results, this study will be conducted by both computational and experimental methods.The experiment method prepared by applying hotwire probe on the center point of the synthetic jet orifice, so from here the researcher get the Ux (average airflow velocity from membrane movement)in a low voltage signal, then the data will be transferred to analog data converter within the record speed 10.000 data/s. The cavities shapes that will be applied are half-sphere, tubes, and conical. The diameter varieties of the orifice are 3 mm, 5 mm and 8 mm. the simulation is started by utilizing the flow rate data from the experiment which can be put in the simulation boundary condition. Furthermore, from visual data of flow contour from CFD simulation the qualities vortex ring formation from SJA can be determined. Based on this research result, the formation of vortex ring occurs at the configuration B3, T3, T5, K3 and K5 of the SJA. Meanwhile, the other types of the synthetic jet cavity which have 8 mm of orifice diameter is not producing the vortex ring.