کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1719885 1520253 2015 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Ships with ventilated cavitation in seaways and active flow control
ترجمه فارسی عنوان
کشتی هایی با حفره تهویه در راه های دریایی و کنترل جریان فعال
کلمات کلیدی
هیدرودینامیک، امواج، کاهش کشش کشتی، کنترل جریان فعال
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی دریا (اقیانوس)
چکیده انگلیسی


• Ship bottom ventilated cavitation as drag reduction technology.
• The ability of this technology to withstand the sea wave impact.
• The fundamentals of active flow control for the ship bottom ventilated cavitation are considered here on the basis of a special computational model of cavitating flows.

Bottom ventilated cavitation has been proven as a very effective drag reduction technology for river ships and planning boats. The ability of this technology to withstand the sea wave impact usual for seagoing ships depends on the ship bottom shape and could be enhanced by some active flow control devices. Therefore, there is the need in numerical tools to estimate the effects of bottom changes and to design such devices. The fundamentals of active flow control for the ship bottom ventilated cavitation are considered here on the basis of a special model of cavitating flows. This model takes into account the air compressibility in the cavity, as well as the multi-frequency nature of the incoming flow in wavy seas and of the cavity response on perturbations by incoming flow. The numerical method corresponding to this model was developed and widely manifested with an example of a ship model tested in a towing tank at Froude numbers between 0.4 and 0.7.The impact of waves in head seas and following seas on cavities has been studied in the range of wavelengths from 0.45 to 1.2 of the model (or ship) length. An oscillating cavitator-spoiler was considered as the flow controlling devices in this study. The oscillation magnitude and the phase shift between cavitator oscillation and the incoming waves have been varied to determine the best flow control parameters. The main results of the provided computational analysis include oscillations of cavity surface, of the pressure in cavity and of the moment of hydrodynamic load on the cavitator. The major part of computations has been carried out for the flap oscillating at the frequency coinciding with the wave frequency, but the effect of a frequency shift is also analyzed.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Ocean Research - Volume 50, March 2015, Pages 163–172
نویسندگان
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