14209

1299 دكتري

دكتري

تبديل انرژي

اصفهان : دانشگاه صنعتي اصفهان

1397

بيست، [۱۸۴]ص.: مصور، جدول، نمودار

احمد سوهانكار

ابراهيم شيراني، مجتبي دهقان منشادي

حسين احمدي كيا، عليرضا مستوفي زاده، محسن ثقفيان، مهدي نيلي احمدآبادي

1397/10/10

كتابنامه

مكانيك

مهندسي مكانيك

ID1299 دكتري

1 Experimental and numerical investigation of the flow over two staggered cylinders with square cross section Jaber Aboueian Jahromi E mail aboueian@gmail com September 17 2018 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran1st Supervisor s Name Ahmad Sohankar E mail asohankar@cc iut ac ir1st Advisor s Name Ebrahim Shirani 2nd Advisor s Name Mojtaba Dehghan Manshadi Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Mechanical and Aerospace Engineering Department Malek Ashtar University of Technology Isfahan IranAbstract Both numerical and experimental investigations are carried out to understand the behavior ofdifferent flow structures around two finite surface mounted square cylinders with aspect ratioof 7 in staggered arrangement The square cylinders are located on a line with a staggeredangle of 45 to the oncoming velocity In this work firstly the laminar 2D flow aroundtwo infinite staggered square cylinders was numerically investigated in a low Reynoldsnumber Re 150 for different gap spacing between the cylinders 0 1 G 6 Based on thispart of investigation it was found that the dominant frequency is an important tool to identifythe different flow regimes These regimes was denoted in this study as single body periodicgap flow aperiodic modulated periodic and synchronized vortex shedding regimes In thesecond part of numerical study large eddy simulations were employed in a high Reynoldsnumber Re 22000 to simulate the turbulent flow around two staggered 3D surface mounted square cylinders Three different flow regimes were identified in this case includingsingle body modulated periodic and synchronized vortex shedding regimes Using theexperimental facilities at Isfahan University of Technology some experiments includingsmoke flow visualization surface pressure measurements and hot wire anemometry arecarried out and their results are analyzed and compared with the current numerical data Forthe smoke flow visualization tests the flow characteristics around two infinite staggeredsquare cylinders at 45 was investigated for different gap distances between cylinders atRe 750 Furthermore for the hot wire anemometry tests the flow field around 3D geometryat Re 22000 was investigated Finally for the pressure tests the effect of the flow around3D geometry on the pressure field on the surfaces of cylinders was studied for different gapdistances at Re 60000 Based on the smoke visualization tests three distinct flow regimeswere recognized i e single body periodic gap flow and modulated periodic flow regime Inaddition two flow regimes were detected for the pressure tests single body and modulatedperiodic flow regimes Finally for the hot wire tests three various flow regimes wereobserved including single body modulated periodic and synchronized vortex sheddingregimes The various features of different flow regimes in the experimental studies of thepressure measurements and the hot wire anemometry have been found to be qualitativelycompatible with those of large eddy simulations Qualitatively some similarities have beenobserved in the flow pattern and other results between 2D and 3D geometries of the presentresearch although there are significant differences between quantitative results is some cases Key Words flow around cylinders vortex shedding staggered configuration numericalmethods large eddy simulation experimental methods wind and smoke tunnel hot wire

احمد سوهانكار

ابراهيم شيراني، مجتبي دهقان منشادي

حسين احمدي كيا، عليرضا مستوفي زاده، محسن ثقفيان، مهدي نيلي احمدآبادي