بررسي رفتار ديناميكي لوله‌هاي مفصلي حامل سيال با سرعت هارمونيك با استفاده از روش مقياس زماني چندگانه

Dynamic Behavior of Articulated Pipes Conveying Fluid With Harmonic Velocity Using the Method of Multiple time scales

ﺳﺎزه ﻫﺎي در ﺗﻤﺎس ﺑﺎ ﺳﯿﺎل ﺑﻪ ﻋﻨﻮان ﺷﺎﺧﻪ اي از زﻣﯿﻨﻪ اﻧﺪرﮐﻨﺶ ﺳﺎزه-ﺳﯿﺎل )FSI(، از ﺟﻤﻠﻪ ﻣﺪل ﻫﺎي ﻓﯿﺰﯾﮑﯽ ﻫﺴﺘﻨﺪ ﮐﻪ ﺑﻪ ﻋﻠﺖ داﺷﺘﻦ دﯾﻨﺎﻣﯿﮏ ﺑﺴﯿﺎر ﻏﻨﯽ ﺗﻮاﻧﺴﺘﻪ اﻧﺪ، ﺧﻮد را ﺑﻪ ﻋﻨﻮان ﯾﮏ ﻧﻤﻮﻧﻪ ﺟﺪﯾﺪ از ﺳﯿﺴﺘﻢ ﻫﺎي دﯾﻨﺎﻣﯿﮑﯽ ﻣﻄﺮح ﻧﻤﺎﯾﻨﺪ و ﻣﻮرد ﺗﻮﺟﻪ ﻓﺮاوان داﻧﺸﻤﻨﺪان ﻗﺮار ﮔﯿﺮد. در اﯾﻦ ﻣﻘﺎﻟﻪ ، رﻓﺘﺎر دﯾﻨﺎﻣﯿﮑﯽ دو ﻟﻮﻟﻪ ﺻﻠﺐ ﻣﺴﺘﻘﯿﻢ ﻣﻔﺼﻠﯽ ﺣﺎﻣﻞ ﺳﯿﺎل ﻣﻄﺎﻟﻌﻪ ﺷﺪه اﺳﺖ. ﺳﺮﻋﺖ ﺳﯿﺎل در ﻟﻮﻟﻪ ﻫﺎ ﻫﺎرﻣﻮﻧﯿﮏ اﺳﺖ. ﺑﺎ اﺳﺘﻔﺎده از ﻣﻌﺎدﻻت ﻻﮔﺮاﻧﮋ، ﺳﯿﺴﺘﻢ داراي دو ﻣﻌﺎدﻟﻪ دﯾﻔﺮاﻧﺴﯿﻞ ﮐﻮﭘﻠﻪ ﺑﺎ ﺿﺮاﯾﺐ ﻣﺘﻐﯿﺮ اﺳﺖ. ﺑﺮرﺳﯽ دﻗﺖ و ﺻﺤﺖ روش ﻣﻘﯿﺎس زﻣﺎﻧﯽ ﭼﻨﺪ ﮔﺎﻧﻪ ﺗﻮﺳﻂ روش ﻋﺪدي راﻧﮓ-ﮐﻮﺗﺎ ﻣﺮﺗﺒﻪ ﭼﻬﺎرم و ﺗﺤﻘﯿﻘﺎت ﻣﺸﺎﺑﻪ اﻧﺠﺎم ﺷﺪه اﺳﺖ ﮐﻪ ﻧﺘﺎﯾﺞ ﻧﺸﺎن ﻣﯽ دﻫﺪ ﮐﻪ از دﻗﺖ ﻗﺎﺑﻞ ﻗﺒﻮﻟﯽ ﺑﺮﺧﻮردار اﺳﺖ. ﺑﺮاي ﻣﻄﺎﻟﻌﻪ رﻓﺘﺎر دﯾﻨﺎﻣﯿﮑﯽ، از ﻧﻤﻮدارﻫﺎي ﭘﺎﺳﺦ زﻣﺎﻧﯽ و ﺻﻔﺤﻪ ﻓﺎز اﺳﺘﻔﺎده ﺷﺪه اﺳﺖ؛ ﺑﺪﯾﻦ ﻣﻨﻈﻮر ﺗﺎﺛﯿﺮ ﭘﺎراﻣﺘﺮﻫﺎي ﻣﻮﺛﺮ از ﻗﺒﯿﻞ ﺳﺮﻋﺖ اوﻟﯿﻪ ﺳﯿﺎل ، ﻧﺴﺒﺖ ﺟﺮم ﺳﯿﺎل ﺑﺮ ﻣﺠﻤﻮع ﺟﺮم ﺳﯿﺎل و ﺟﺮم و لوله y فركانس سرعت B در نمودارهاي ﭘﺎﺳﺦ زﻣﺎﻧﯽ و ﺻﻔﺤﻪ ﻓﺎز ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن ﻣﯽ دﻫﺪ، ﺑﺎ اﻓﺰاﯾﺶ uo و B و كاهش y ، آﺷﻔﺘﮕﯽ و ﺑﯽ ﻧﻈﻤﯽ دﯾﻨﺎﻣﯿﮑﯽ ﺳﯿﺴﺘﻢ اﻓﺰاﯾﺶ ﯾﺎﻓﺘﻪ و ﺳﯿﺴﺘﻢ ﺑﻪ ﺳﻤﺖ ﻧﺎﭘﺎﯾﺪار ﺷﺪن ﮐﺸﯿﺪه ﻣﯽ ﺷﻮد.

Fluid contact structures as a branch of the Fluid–Structure Interaction (FSI) are among the physical models that have been able to present themselves as a new example of dynamic systems due to their very rich dynamics and Pay close attention to scientists. The dynamic behavior of two rigid straight articulated pipes conveying fluid is studied. The flow rate in the pipe is harmonic. The numerical results are compared with the present method and Runge–kutta 4th order for validation and an acceptable match between them is obtained. The method of multiple time scales is used to drive the time response and phase plane curves. The influence of the initial velocity , ratio fluid mass per total fluid mass and mass of pipes and flow frequency on the time response and phase plane curves are examined. The results show, by increasing "u" _"0" and and decreasing the system is closer to loss of stability and increasing dynamic chaos.