CAJ | 학술논문

采用烟线和 PIV 实验研究犚犲＝22400时直径与厚度比犇/犎＝5圆盘近尾迹（狓/犇＜5）流场结构。流向平面烟线显示表明圆盘尾迹有稳定的回流区和随机扭曲倾斜的三维涡旋结构。对烟线平面 PIV 测速数据统计平均，发现该回流区具有较好的对称性，且长度为2．1犇。对 PIV 数据进行 POD 重构，发现流向雷诺正应力和切应力峰值出现在回流区两侧剪切层，横向雷诺正应力峰值出现在回流区驻点附近，其正是烟线显示涡旋结构脱落区域。圆盘尾迹涡旋结构的产生和脱落源于剪切层的不稳定性及其与回流区的相互作用。圆盘尾迹前两个模态含能仅为10．9％和10．2％，表明湍流结构的随机性；前10个模态含能45．9％可较好描述流场的平均雷诺切应力。
채용연선화 PIV 실험연구위시＝22400시직경여후도비분/봉＝5원반근미적（피/분＜5）류장결구。류향평면연선현시표명원반미적유은정적회류구화수궤뉴곡경사적삼유와선결구。대연선평면 PIV 측속수거통계평균，발현해회류구구유교호적대칭성，차장도위2．1분。대 PIV 수거진행 POD 중구，발현류향뢰낙정응력화절응력봉치출현재회류구량측전절층，횡향뢰낙정응력봉치출현재회류구주점부근，기정시연선현시와선결구탈락구역。원반미적와선결구적산생화탈락원우전절층적불은정성급기여회류구적상호작용。원반미적전량개모태함능부위10．9％화10．2％，표명단류결구적수궤성；전10개모태함능45．9％가교호묘술류장적평균뢰낙절응력。
Using smoke wires and PIV technique,the near wake(X/D<5 )of circular disk with an aspect of D/H =5 at Re=22400 was experimentally studied.Flow visualization using smoke wires showed that there was a stable recirculation zone and stochastic,distorted and tilted three-dimensional vortices behind the disk.By statistic average analysis of a series of cartogra-phies obtained by PIV technique,it was found that the mean flow field was symmetric with a re-circulation zone in length of 2.1D.POD analysis was applied to the PIV data,reconstruction of the first pair of eigenmodes manifested that the peaks of u2 and uv located in the shear layer be-tween the free stream and the recirculation zone,and the peak of V2 appeared near the stagnation point of the recirculation zone,where vortices were shedding displayed by smoke wires.As a conclusion,vortices generation and shedding in the wake originated from shear layer instability and its interaction with the recirculation zone.The first and second POD modes represent only 10.9% and 10.2% of total turbulent kinetic energy,which means that turbulence structures is relatively stochastic.The first ten modes represent 45.9% of total energy,therefore,the mean Reynolds shear stress can be well described.