The flow-surface interaction and resulting pockets is the case of a turbulence boundary layer. Conditionally sampled hot-wire measurements within the wall region show that a strong vortex forms within the pocket, bordering the upstream portion, which stay in the wall region. This vortex is the result of the rearrangement of existing sublayer vorticity and its amplification. The work in this area has been applied to the prediction and reduction of drag. The study is focused on determining change in the length scale of the pockets. An important relationship between pocket and modified wall has been found. By changing the upstream boundary condition at the wall, the length scale of pockets were decreased.

ABSTRACT
1. 서 론
2. 실험장치 및 방법
    2.1 저속 풍동
    2.2 가시화 마커 분사
    2.3 밝은 조명
    2.4 고속 사진촬영 시스템
    2.5 속도 데이터 취득 시스템
    2.6 벽면의 형상 변화
    2.7 평균속도 프로파일 데이터 처리 기술
    2.8 가시화 데이터
    2.9 포켓 측정방법
3. 결과 및 고찰
    3.1 평균속도 프로파일 데이터
    3.2 포켓 length scale
4. 결 론
References

• 유성출(Dept. of mechanical & automotive Engr., Halla University) | Seoung-Chool Yoo
• 조장현(Dept. of mechanical & automotive Engr., Halla University) | Jang-Hyen Jo Corresponding Author