يافتن فاصله بهينه و بررسي تاثير سطح مقطع جسم كنترلي بر كاهش اثرات ارتعاشات ناشي از گردابه‌ها در ناحيه قفل‌شدگي

هدف از انجام پژوهش حاضر، بررسي پديده ارتعاشات ناشي از گردابه‌ها و كاهش اثرات آن با بهره‌گيري از جسم كنترلي مي‌باشد. به همين منظور ابتدا سيلندر استوانه‌اي شكل قرار گرفته بر روي بستر الاستيك و در معرض جريان يكنواخت سيال شبيه‌سازي مي‌گردد. پس از مقايسه نتايج به دست آمده با ساير پژوهش‌هاي عددي و آزمايشگاهي مشابه و اطمينان از دقت و صحت نتايج، جسم كنترلي با سطح مقطع دايره‌اي و در 5 نسبت فاصله مختلف در پشت سيلندر اصلي قرار داده مي‌شود و ضمن بررسي تاثير آن بر ضرايب ليفت و درگ ميانگين و ماكزيمم دامنه نوسانات در ناحيه قفل‌شدگي، فاصله بهينه قرارگيري سيلندر كنترلي تعيين مي‌گردد. سپس به بررسي تاثير تغيير الگوي قرارگيري و سطح مقطع جسم كنترلي پرداخته مي‌شود. به همين منظور ابتدا تاثير قرارگيري دو سيلندر كنترلي به صورت هم‌راستا و عمود بر جريان در فاصله بهينه بدست آمده مورد مطالعه قرار مي‌گيرد. در انتها تاثير استفاده از جسم‌هاي‌ كنترلي با سطح مقطع‌هاي مختلف و غيردايروي كه قطر هيدروليكي برابر با سيلندر اصلي دارند، بررسي مي‌گردد. The objective of this study is to examine the phenomenon of vortex-induced vibrations and reduction of its effects using the control body. For that reason, first the circular cylinder located on the elastic foundation and subjected to uniform fluid flow, is simulated.After comparing the obtained results with those of other similar numerical and laboratory investigations and ensuring the accuracy and correctness of the results, the control body with a circular cross-section is placed behind the master cylinder at 5 different distance ratios and examining its effect on the mean lift and drag coefficients and maximum amplitude of oscillations in lock-in area and the optimal configuration and location of control cylinders are defined. Then, the effect of changing the arrangement and cross-section of the control body are studied. For that reason, first the effect of two control cylinders in parallel and perpendicular arrangement to the current at the optimal distance are studied. Finally, the impact of using the control bodies with different noncircular cross-sections, which have hydraulic diameter equal to the master cylinder, are investigated.

The objective of this study is to examine the phenomenon of vortex-induced vibrations and reduction of its effects using the control body. For that reason, first the circular cylinder located on the elastic foundation and subjected to uniform fluid flow, is simulated.After comparing the obtained results with those of other similar numerical and laboratory investigations and ensuring the accuracy and correctness of the results, the control body with a circular cross-section is placed behind the master cylinder at 5 different distance ratios and examining its effect on the mean lift and drag coefficients and maximum amplitude of oscillations in lock-in area and the optimal configuration and location of control cylinders are defined. Then, the effect of changing the arrangement and cross-section of the control body are studied. For that reason, first the effect of two control cylinders in parallel and perpendicular arrangement to the current at the optimal distance are studied. Finally, the impact of using the control bodies with different noncircular cross-sections, which have hydraulic diameter equal to the master cylinder, are investigated