# Case 5 : LRN Airfoil

## Introduction

 • Low Reynolds Number Airfoil은 저속비행 및 고고도 항공기 등에 주로 활용됨\
 • 정확한 항력 계산을 위해 Transition 해석이 필요\
 • Laminar Separation bubble에 의한 non-linear한 양력 증가 발생\
 • EFD와 CFD 결과간의 차이를 분석하고 원인을 규명할 필요 있음

![Transition Estimation](/files/-LLhClLjFI5ohqNn5gbx)

![Non-Linear Lift Increasement](/files/-LLhDWo7gnzX0rmwFPqN)

## Wind Tunnel Test

**일본 Tohoku 대학의 화성 풍동 사용**  

![화성 풍동 외부](/files/-LLhEMRyV-r5ngIuVBaI)

![화성 풍동 내부](/files/-LLhEwbDiDPh1oU-HBTl)

![화성 풍동 계측부](/files/-LLhFFmnCFH0p93JcXCh)

![실험 모델 장착부](/files/-LLhGA2uopqf1qxtbykZ)

**풍동 정보**\
 • 풍동 종류 : 밀폐형 풍동\
 • 작동 유체 : 공기\
 • 난류 강도 : 0.5%\
 • 측정부 면적 : 100 mm X 150 mm

![측정부](/files/-LLhI6fgL9DejZDzklXL)

**실험 모델**  \
 • 3D 프린터로 제작\
 • 코드 길이 : 50 mm\
 • 스팬 길이 : 100 mm

![실험 모델](/files/-LLhGqLZMT6FvPEbOnF6)

**실험 조건**\
 • M = 0.48\
 • Re = 27,500

## Result

**양력 계수**\
&#x20;<img src="/files/-LLhNVKp5geuKVkRWEa5" alt="" data-size="original">&#x20;

![받음각 변화에 따른 양력 계수 분포 비교 결과](/files/-LLhR78X5C8iPI-NI64r)

![받음각 변화에 따른 천이 발생 지점 변화](/files/-LLhRFjTgyWwUAU2Z027)

![NACA 0012-23 Airfoil 결과](/files/-LLhRJltdbWWgeXh0Efx)

## &#x20;Attached files

&#x20;• Case5\_Low-Reynold-Airfoil        : Case 5 소개 자료\
&#x20;• Case5\_shape\_geo\_open.IGS     : Case 5 형상 자료(IGS 형식)\
&#x20;• Case5\_shape\_geo\_open.STEP  : Case 5 형상 자료(STEP 형식)\
&#x20;• Case5\_Result\_1\_AoACl.dat        : Case 5 상세 결과(NACA 0012-34 Airfoil)\
&#x20;• Case5\_Result\_2\_AoACl.dat        : Case 5 상세 결과(LRN Airfoil)

{% file src="/files/-LLhTIwfkSU31rSFQSdT" %}

{% file src="/files/-LLhTOP5k9FlH4ZjNhXl" %}

{% file src="/files/-LLhTQXG9afMFRErYPkL" %}

{% file src="/files/-LLhWplg2jiovv-q6wki" %}

{% file src="/files/-LLhWtFyIKZfzEZuN8Rr" %}


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