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Abstrak :
Sejalan dengan perkembangan peradaban, kehidupan manusia tidak bisa terlepas dari berbagai peralatan elektronika yang memiliki banyak sekali komponen seperti: transistor, kapasitor, resistor, dll. Komponen elektronik ini memancarkan panas sewaktu mereka beroperasi, sehingga untuk mengatasi masalah ini, diperlukan suatu sistem pendinginan yang efektif. Kebanyakan dari system pendinginan komponen elektronika yang dipakai sekarang ini berbasis pada fan. Namun sistem ini semakin tidak memadai dengan perkembangan teknologi elektronika yang semakin mengarah pada miniaturisasi produk. Sebagai alternatif pengganti sistem berbasis fan ini, manusia mengembangkan suatu alat yang disebut jet sintetik. Jet sintetik memiliki dimensi yang relatif kecil, tingkat kebisingan yang lebih kecil, lebih sedikit memancarkan panas dan yang paling penting jet sintetik memiliki efisiensi pendinginan yang lebih besar dibanding fan. Thesis ini membahas hasil penelitian yang dilakukan terhadap 4 prototype desain original jet sintetik dengan menggunakan kombinasi pendekatan komputasi dan eksperimen. Tahap komputasional pada penelitian ini dilakukan dengan menggunakan software CFD Fluent dengan model turbulensi k-ω SST dengan elemen meshing Tet/Hybrid tipe Tgrid untuk melihat distribusi aliran pada jet sintetik. Sedangkan pada tahap eksperimental akan dipelajari karakteristik perpindahan panas konveksi dengan variasi jenis gelombang sinusoidal, triangle dan square pada frekuensi 80 Hz, 120 Hz dan160 Hz. ......In line with the development of civilization, human life can not be separated from a various electronic equipment that has many components such as transistors, capacitors, resistors, etc. These electronic components emits heat when they operate, an effective cooling system is required in order to overcome this problem. Most of the electronic component cooling systems used today are based on the fan. But this system is inadequate to the development of electronics technology that increasingly lead to the product miniaturization. As an alternative to this fan-based system, humans developed a device called synthetic jet. Synthetic jets have relatively small dimensions, smaller noise level, emits less heat and the most important that synthetic jet has a greater cooling efficiency than fan. This thesis discusses the results of research conducted on four original designed synthetic jet prototype using a combination of computational and experimental approaches. Computational phase was conducted using Fluent CFD software with k-ω SST turbulence model with meshing elements of the Tet / Hybrid type Tgrid to see the flow distribution in the synthetic jet. While the experimental phase will be studied at the convective heat transfer characteristics with variations in type of sinusoidal wave, triangle and square at a frequency of 80 Hz, 120 Hz dan160 Hz.

Abstrak :
Lightning current waves are resulted by electric discharge from the clouds to the ground These waves are stated as a wave-front time and wave-tail time. The comparation between the wave-tail time and the wave front time defined as a constant "k". A mathematical approach to determine the impulse wave which base on the constant "k" has been published however these were limited by the big constant "h" or the wave which has a long tail. This paper will explain how to determine the constant "lc" of impulse wave which has a short and long tail. The constant "k" resulted from the experiment will be applied to determine the impulse wave. The comparation from the experiment and mathematical approach resulting very satisfactory outcome.