유전적 알고리듬을 이용한 3차원 PTV기법의 구축과 원주 근접후류 유동특성에 관한 연구

Abstract

In order to verify the capability of the constructed measurement system, a performance test was made using a set of virtual images on a impinging jet. After confirming the performances of the constructed system, the system was applied to the measurement of flow characteristics of the wake of a circular cylinder.

The belows are the summary of the thesis.

GA based 3D-PTV system for the measurement of complex flow structure are constructed in the first half of the thesis.

The performances test on the constructed system is made using the sets of virtual images generated by a LES data set on a impinging jet flow. Through this test it is verified that the vector recovery ratio becomes higher three times than those of other studies. It is shown that about 1,100 three-dimensional instantaneous velocity vectors is obtained in an actual experiment, which implies that the recovery ratio is more than over about 65%. This percentage is most highest among other three-dimensional PTV techniques.

The constructed system having the above performances is applied to the measurement of the flow field near the wake of a circular cylinder and turbulent characteristics of the flow such as turbulent intensity, Reynolds stresses, turbulent kinetic energy are measured by the constructed system. Good qualitative and quantitative results on the turbulent properties are shown.

Lastly, it is shown that the constructed 3D-GA-PTV system will be able to be used for the investigation of the turbulent characteristics of complex flows since the number of 3D velocity vectors obtained by the system is big enough than the limits, 700, for probing the turbulences of complex flows.