نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشگاه جامع امام حسین (ع)- دانشکده فنی و مهندسی - گروه مکانیک

2 دانشگاه صنعتی شریف- دانشکده مکانیک- آزمایشگاه دریایی

3 محقق سازمان تحقیقات و خودکفایی

چکیده

استفاده از پله های عرضی در کف بدنه شناورهای تندرو سرشی، یکی از روش های افزایش سرعت آنها است. این شناورها دارای یک قله در منحنی "مقاومت-سرعت" خود و در مرحله ابتدایی فاز سرشی هستند. این قله در عمل بار زیادی را بر سیستم محرکه این شناورها وارد می نماید. در این مقاله ابتدا رفتار هیدرودینامیکی دو مدل بدنه، یکی بدون پله عرضی و دیگری با یک پله عرضی در حوضچه کشش بررسی تجربی شده اند. سپس درحالیکه یک سیستم تزریق هوای طبیعی به پشت پله عرضی مدل دوم اضافه شده بود، آزمایش های مجددا تکرار گردیدند. نتایج نشان می دهند که در قبل از مرحله سرشی، بدنه پله دار دارای مقاومت بیشتری به میزان 30 تا 40 درصد بوده و پس از مرحله سرش، مقاومت بدنه پله دار حدود 5% کمتر است. استفاده از سیستم هوادهی خود تغذیه، باعث می گردد تا علاوه بر کاهش مقاومت کل بدنه در قبل از مرحله سرش، مقدار مقاومت شناور در قله منحنی مقاومت نیز تا حدود 21 درصد کاهش یابد. نتایج نشان می دهند که هوادهی به پشت پله می تواند راهکاری مناسب وکم هزینه برای کاستن قله منحنی "مقاومت- سرعت" در شروع مرحله سرشی این شناورها باشد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Experimental Analysis of the Effects of Ventilating behind Transverse Step of High-speed Planning Boats on Reducing of their Resistance Hump

چکیده [English]

Utilizing transverse steps for high-speed planning hulls is one of the methods for reducing of their resistance and thereafter increasing of their speed. Similar to regular planning hulls, the stepped hulls also have a hump in their resistance-speed curves during the transition from displacement to planning stage. Overcome to the hump usually follows with a heavy load on propulsion systems. In this paper, hydrodynamic characteristics of two planning boat model, a regular V-bottom hull and a hull with one transverse step, are investigated experimentally using towing tank tests. After that the tests for the stepped hull are repeated while a ventilation system is also added behind the transverse step. The results show in preplanning stage, resistance of the stepped hull increased about 30 to 40 percent whereas at the planning stage their resistance reduced about 5 percent respect to the regular planning hull. Using a natural ventilated system for stepped planning hulls reduced both the hump resistance (about 21 percent) and preplanning resistance respect to non-ventilated stepped hull. So, it can be used as a low cost system for practical issues.

کلیدواژه‌ها [English]

  • Hydrodynamics
  • High Speed Planning Boats
  • Measurements
  • Ventilated Step
  • Towing tank

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