PENGARUH PICH RATIO TERHADAP KARAKTERISTIK GETARAN PADA ALIRAN FLUIDA YANG MENGALAMI SELF EXCITED VIBRATIONS
DOI:
https://doi.org/10.26905/jtmt.v6i2.4541Keywords:
Aliran Fluida, Pinch Ratio, Unstable Flow, Self-Excited VibrationsAbstract
Mekanisme terjadinya self excited vibrations diawali dengan adanya perubahan arah aliran fluida didalamselang (flexible pipe) saat melewati daerah jepitan (pinch area). Perubahan penampang selang akanmempengaruhi arah vektor aliran yang menyebabkan aliran fluida tidak stabil (unstable). Selain itu fluidamempunyai energi yang diperoleh dari pompa terdiri dari energi tekanan dan kecepatan sesuai dengan hukumBernoulli. Pada saat melewati daerah jepitan, terjadi pertukaran energi antara energi tekanan dan energikecepatan secara bergantian menyebabkan terjadinya fluktuasi aliran yang berdampak pada munculnyagetaran pada selang yang dicirikan dengan frekwensi getarannya. Berdasarkan persamaan model matematismenunjukkan bahwa perubahan rasio jepitan antara 0,66 s/d 0,68 menghasilkan frekwensi model antara9,75 hz s/d 7,12 hz. Hal ini menunjukkan perbedaan dengan hasil pengujian dimana semakin besar rasiojepitan terjadi penurunan amplitudo yang diikuti dengan peningkatan frekwensi sebagai akibat pertukaranenergi tekanan menjadi energi kecepatan.References
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