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    κ³΅μœ κ³΅κ°„ κ°€μΉ˜ μ€‘μ‹¬μœΌλ‘œ

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    ν•™μœ„λ…Όλ¬Έ(석사)--μ„œμšΈλŒ€ν•™κ΅ λŒ€ν•™μ› :ν™˜κ²½λŒ€ν•™μ› ν™˜κ²½κ³„νšν•™κ³Ό,2019. 8. λ°•μΈκΆŒ.One of the most noticeable changes in the type of household in Korea recently is the surge in single-person households. As of 2016, 27.9 percent of korean households were single-person households, with 34.8 percent of them being young people in their 20s and 30s. However, the Korean housing market, which until recently had been mainly supplied to four-member households, has a structural limitation that does not fully reflect the change in types of households due to the surge in single-person households or their ability to cover housing costs. In particular, the housing cost burden was aggravated by the housing supply provided without considering the economic burden capacity of the young generation and accelerated their inclusion into the housing vulnerable class. Meanwhile, the concept of shared space in a shared economy began to be introduced into residential space to overcome the difficulties of securing Affordable Housing for the younger generation. In particular, the share house, which was introduced in earnest in 2013 around the downtown, is seen as a solution to the reduction of housing cost burden while reflecting the characteristics of the young generation's housing demand by applying the concept of shared space differentiated from the previous housing units. In addition, the shared space of a share house is a public space with the characteristics of a private area and a private space, which has high economic and social benefits for residents who use it together. Therefore, shared space is a key space that evokes the housing demand characteristics of the share house and is a factor that should be addressed in this study. In this background, the purpose of this study was to examine the characteristics of the housing demand of young single household through the analysis of the effect on the share-house rent based on the characteristics of the shared space, and in particular, the value of the shared area relative to the dedicated area of the share house was empirically analyzed. The results obtained through the analysis are as follows: First, it has been shown that one young household living in a sharehouse has a considerably higher payment for securing an independent private space. This seems to be the result of Sherhouse's characteristics of sharing residential space within the housing unit, which makes the desire for personal privacy stronger. Second, young people living in a share house confirmed that there was a positive payment for a wide and pleasant public space instead of using a small private space. This is a positive demand for sharing the rest of the space except for private bedrooms, which shows the potential for a new way of living using shared space in the future. Third, the difference between the value of exclusive area and the value of shared area per unit area was found to exist. The analysis shows that 1㎑ of exclusive area can be traded with 12.86㎑ of shared area, which is empirically established that the value of space can vary depending on its characteristics and how it is used, even though it is a residential area within the same housing unit. This study comprehensively examined the characteristics of the supply of share houses in the rental housing market, and empirically analyzed the housing demand characteristics of young single-person households. In particular, the significance of the study that the data on the shared area of a share house was constructed based on legal understanding and the quantitative results on the value of shared space in the coming shared economy society were presented through the analysis of the determinants of the share house rent based on it.졜근 μš°λ¦¬λ‚˜λΌμ˜ 가ꡬ μœ ν˜•μ— μžˆμ–΄μ„œ κ°€μž₯ λ‘λ“œλŸ¬μ§€λŠ” λ³€ν™” 쀑 ν•˜λ‚˜λŠ” 1인 κ°€κ΅¬μ˜ 급증이닀. 2016λ…„ κΈ°μ€€ κ΅­λ‚΄ κ°€κ΅¬μ˜ 27.9%κ°€ 1인 가ꡬ이며, 이 쀑 20β‹…30λŒ€ μ²­λ…„ 1인 가ꡬ가 μ°¨μ§€ν•˜λŠ” λΉ„μœ¨μ€ 34.8%에 이λ₯΄λ €λ‹€. ν•˜μ§€λ§Œ μ΅œκ·ΌκΉŒμ§€ 4인 가ꡬ μœ„μ£Όλ‘œ κ³΅κΈ‰λ˜μ–΄ μ™”λ˜ μš°λ¦¬λ‚˜λΌ μ£Όνƒμ‹œμž₯은 μ²­λ…„ 1인 가ꡬ 급증에 λ”°λ₯Έ 가ꡬ μœ ν˜•μ˜ λ³€ν™”λ‚˜ μ΄λ“€μ˜ μ£Όκ±°λΉ„ λΆ€λ‹΄λŠ₯λ ₯을 μΆ©λΆ„νžˆ λ°˜μ˜ν•˜μ§€ λͺ»ν•˜λŠ” ꡬ쑰적인 ν•œκ³„λ₯Ό 가진닀. 특히 μ²­λ…„μ„ΈλŒ€λ“€μ˜ 경제적 λΆ€λ‹΄ λŠ₯λ ₯을 κ³ λ €ν•˜μ§€ μ•Šμ€ 채 κ³΅κΈ‰λ˜λŠ” μ£Όνƒλ“€λ‘œ μΈν•˜μ—¬ μ£Όκ±°λΉ„ 뢀담은 μ‹¬ν™”λ˜μ—ˆμœΌλ©° 이듀이 μ£Όκ±°μ·¨μ•½κ³„μΈ΅μœΌλ‘œ νŽΈμž…λ˜λŠ” 것을 κ°€μ†ν™”ν•˜μ˜€λ‹€. ν•œνŽΈ μ²­λ…„μ„ΈλŒ€μ˜ λΆ€λ‹΄ κ°€λŠ₯ν•œ 주택(Affordable Housing) ν™•λ³΄μ˜ 어렀움을 κ·Ήλ³΅ν•˜κ³ μž 곡유경제의 κ³΅μœ κ³΅κ°„ κ°œλ…μ΄ 주거곡간에 λ„μž…λ˜κΈ° μ‹œμž‘ν•˜μ˜€λ‹€. 특히 2013λ…„ 도심을 μ€‘μ‹¬μœΌλ‘œ 본격적으둜 λ„μž…λœ μ…°μ–΄ν•˜μš°μŠ€λŠ” 이전 μ£Όνƒλ“€κ³ΌλŠ” μ°¨λ³„ν™”λœ κ³΅μœ κ³΅κ°„ κ°œλ…μ„ 주거에 μ μš©ν•¨μœΌλ‘œμ¨ μ²­λ…„μ„ΈλŒ€μ˜ μ£Όκ±°μˆ˜μš”νŠΉμ„±μ„ λ°˜μ˜ν•˜λŠ” λ™μ‹œμ— μ΄λ“€μ˜ μ£Όκ±°λΉ„ λΆ€λ‹΄ 경감에 λŒ€ν•œ ν•΄κ²°λ°©μ•ˆμœΌλ‘œ 보인닀. λ˜ν•œ μ…°μ–΄ν•˜μš°μŠ€μ˜ κ³΅μœ κ³΅κ°„μ€ 사적 μ˜μ—­μ˜ κ³΅μœ ν™”, μ „μš©κ³΅κ°„μ˜ 성격을 μ§€λ‹Œ κ³΅μš©κ³΅κ°„μœΌλ‘œμ„œ ν•¨κ»˜ μ‚¬μš©ν•˜λŠ” κ±°μ£Όμžλ“€μ—κ²Œ κ²½μ œμ γ†μ‚¬νšŒμ  μΈ‘λ©΄μ—μ„œ 높은 효용과 영ν–₯을 λ―ΈμΉ˜λŠ” 곡간이닀. λ”°λΌμ„œ κ³΅μœ κ³΅κ°„μ€ μ…°μ–΄ν•˜μš°μŠ€λ§Œμ˜ μ£Όκ±°μˆ˜μš”νŠΉμ„±μ„ λ°œν˜„μ‹œν‚€λŠ” 핡심 κ³΅κ°„μœΌλ‘œμ„œ λ³Έ μ—°κ΅¬μ—μ„œ μ€‘μ μ μœΌλ‘œ 닀루어야 ν•˜λŠ” μš”μΈμ΄λ‹€. μ΄λŸ¬ν•œ λ°°κ²½μ—μ„œ λ³Έ μ—°κ΅¬λŠ” κ³΅μœ κ³΅κ°„ νŠΉμ„±μ„ μ€‘μ‹¬μœΌλ‘œ μ…°μ–΄ν•˜μš°μŠ€ μž„λŒ€λ£Œμ— λ―ΈμΉ˜λŠ” 영ν–₯ 뢄석을 톡해 μ²­λ…„ 1인 κ°€κ΅¬μ˜ μ£Όκ±°μˆ˜μš”νŠΉμ„±μ„ μ‚΄νŽ΄λ³΄λŠ”λ° λͺ©μ μ΄ 있으며, 특히 μ…°μ–΄ν•˜μš°μŠ€μ˜ μ „μš©λ©΄μ  λŒ€λΉ„ 곡유면적의 κ°€μΉ˜λ₯Ό μ‹€μ¦λΆ„μ„ν•˜μ˜€λ‹€. 뢄석을 톡해 λ„μΆœλœ κ²°κ³Όλ₯Ό μ •λ¦¬ν•˜λ©΄ λ‹€μŒκ³Ό κ°™λ‹€. 첫째, μ…°μ–΄ν•˜μš°μŠ€μ— κ±°μ£Όν•˜λŠ” μ²­λ…„ 1인 κ°€κ΅¬λŠ” λ…λ¦½λœ κ°œμΈκ³΅κ°„ 확보에 λŒ€ν•œ μ§€λΆˆ μš©μ˜κ°€ μƒλ‹Ήνžˆ 높은 κ²ƒμœΌλ‘œ λ‚˜νƒ€λ‚¬λ‹€. μ΄λŠ” μ„ΈλŒ€ λ‚΄ 주거곡간을 ν•¨κ»˜ μ‚¬μš©ν•˜λŠ” 것을 μ „μ œλ‘œ ν•œ μ…°μ–΄ν•˜μš°μŠ€μ˜ νŠΉμ„±μ΄ 개인 ν”„λΌμ΄λ²„μ‹œ 보μž₯에 λŒ€ν•œ μš•κ΅¬λ₯Ό 더 κ°•ν•˜κ²Œ λ§Œλ“œλŠ” 결과둜 보인닀. λ‘˜μ§Έ, μ…°μ–΄ν•˜μš°μŠ€μ— κ±°μ£Όν•˜λŠ” 청년듀은 μž‘μ€ κ°œμΈκ³΅κ°„μ„ μ‚¬μš©ν•˜λŠ” λŒ€μ‹  λ„“κ³  μΎŒμ ν•œ κ³΅μš©κ³΅κ°„μ— λŒ€ν•œ μ–‘(+)적인 μ§€λΆˆ μš©μ˜κ°€ μ‘΄μž¬ν•¨μ„ ν™•μΈν•˜μ˜€λ‹€. μ΄λŠ” 개인 침싀을 μ œμ™Έν•œ λ‚˜λ¨Έμ§€ μ£Όκ±° κΈ°λŠ₯을 κ³΅μœ ν•˜λŠ” 것에 λŒ€ν•œ 긍정적인 μˆ˜μš”κ°€ ν™•μΈλœ κ²°κ³Όλ‘œμ„œ, ν–₯ν›„ κ³΅μœ κ³΅κ°„μ„ ν™œμš©ν•œ μƒˆλ‘œμš΄ κ±°μ£Όλ°©μ‹μ˜ 잠재적 κ°€λŠ₯성을 μ—Ώλ³Ό 수 μžˆλ‹€. μ…‹μ§Έ, λ‹¨μœ„ 면적당 μ „μš©λ©΄μ  κ°€μΉ˜μ™€ 곡유면적 κ°€μΉ˜μ˜ 차이가 μ‘΄μž¬ν•˜λŠ” κ²ƒμœΌλ‘œ λ‚˜νƒ€λ‚¬λ‹€. 뢄석 κ²°κ³Ό μ „μš©λ©΄μ  1γŽ‘λŠ” 곡유면적 12.86γŽ‘μ™€ 거래(trade-off) 될 수 μžˆλŠ” κ²ƒμœΌλ‘œ λ‚˜νƒ€λ‚¬μœΌλ©°, μ΄λŠ” 동일 μ„ΈλŒ€ λ‚΄ μ£Όκ±°κ³΅κ°„μž„μ—λ„ λΆˆκ΅¬ν•˜κ³  κ³΅κ°„μ˜ 성격과 μ΄μš©ν–‰νƒœμ— 따라 κ³΅κ°„μ˜ κ°€μΉ˜κ°€ λ‹¬λΌμ§ˆ 수 μžˆμŒμ„ μ‹€μ¦μ μœΌλ‘œ 규λͺ…ν•œ 것이닀. λ³Έ μ—°κ΅¬λŠ” 졜근 μž„λŒ€μ£Όνƒ μ‹œμž₯μ—μ„œ κΈ‰μ¦ν•˜λŠ” μ…°μ–΄ν•˜μš°μŠ€μ˜ 곡급 νŠΉμ„±μ„ μ’…ν•©μ μœΌλ‘œ μ‚΄νŽ΄λ³΄κ³  이λ₯Ό ν†΅ν•œ μ²­λ…„ 1인 κ°€κ΅¬μ˜ μ£Όκ±°μˆ˜μš”νŠΉμ„±μ„ μ‹€μ¦λΆ„μ„ν•˜μ˜€λ‹€. 특히 κ±΄μΆ•λ¬Όμ˜ 섀계기법 및 건좕물 면적 산정에 λŒ€ν•œ 법적 이해λ₯Ό λ°”νƒ•μœΌλ‘œ μ…°μ–΄ν•˜μš°μŠ€μ˜ 곡유면적 데이터λ₯Ό κ΅¬μΆ•ν•œ 점 그리고 이λ₯Ό ν† λŒ€λ‘œ μ…°μ–΄ν•˜μš°μŠ€ μž„λŒ€λ£Œ κ²°μ •μš”μΈ 뢄석을 톡해 λ‹€κ°€μ˜€λŠ” 곡유경제 μ‚¬νšŒμ˜ κ³΅μœ κ³΅κ°„ κ°€μΉ˜μ— λŒ€ν•œ μ •λŸ‰μ μΈ κ²°κ³Όλ₯Ό μ œμ‹œν•˜μ˜€λ‹€λŠ” μ μ—μ„œ μ—°κ΅¬μ˜ μ˜μ˜κ°€ μžˆλ‹€.제1μž₯ μ„œ λ‘  1 제1절 μ—°κ΅¬μ˜ λ°°κ²½ 및 λͺ©μ  1 제2절 μ—°κ΅¬μ˜ λ²”μœ„ 및 방법 5 제2μž₯ 이둠 및 선행연ꡬ κ³ μ°° 6 제1절 κ³΅μœ κ³΅κ°„ μœ„μƒμ˜ λ³€ν™” 6 1. κ³΅μœ κ³΅κ°„ κ°œλ… κ³ μ°° 6 2. κ³΅μœ μ£Όνƒ(Share House) κ³΅μœ κ³΅κ°„ 8 제2절 μ…°μ–΄ν•˜μš°μŠ€ κ΄€λ ¨ 선행연ꡬ κ³ μ°° 14 1. μ…°μ–΄ν•˜μš°μŠ€ 곡간ꡬ성 및 곡급 νŠΉμ„± 14 2. μ…°μ–΄ν•˜μš°μŠ€ μ£Όκ±°μ„ ν˜Έ μš”μΈ κ³ μ°° 15 3. μ…°μ–΄ν•˜μš°μŠ€ μž„λŒ€λ£Œ κ²°μ •μš”μΈ 뢄석 연ꡬ 17 제3절 μ†Œκ²° 24 제3μž₯ 뢄석틀 26 제1절 λΆ„μ„μžλ£Œ 및 ν‘œλ³Έ 26 제2절 뢄석틀 27 제3절 λ³€μˆ˜ ꡬ성 28 1. μ…°μ–΄ν•˜μš°μŠ€ κ°œλ³„ μΉ¨λŒ€ μž„λŒ€λ£Œ 28 2. μ…°μ–΄ν•˜μš°μŠ€ 곡급 νŠΉμ„± λ³€μˆ˜ 28 제4절 곡유면적 μ‚°μΆœ κ·Όκ±° 32 제4μž₯ 싀증뢄석 35 제1절 μ…°μ–΄ν•˜μš°μŠ€ 곡급 νŠΉμ„± 35 제2절 헀도닉 가격λͺ¨ν˜• 38 1. λ‹€μ€‘νšŒκ·€λͺ¨ν˜• 38 2. μœ„κ³„μ  μ„ ν˜•λͺ¨ν˜• 40 제3절 μ…°μ–΄ν•˜μš°μŠ€ μž„λŒ€λ£Œ κ²°μ • μš”μΈ 43 제4절 μ…°μ–΄ν•˜μš°μŠ€ 곡유면적 κ°€μΉ˜μ— λŒ€ν•œ λ…Όμ˜ 48 제5μž₯ κ²°λ‘  51Maste

    κ±΄κ°•λ³΄ν—˜κ³΅λ‹¨ ν‘œλ³Έ μ½”ν˜ΈνŠΈ 자료λ₯Ό μ΄μš©ν•œ, κ΅­λ‚΄ 심방세동 ν™˜μžμ˜ 사망λ₯ κ³Ό 사망 원인에 κ΄€ν•œ 연ꡬ

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    ν•™μœ„λ…Όλ¬Έ (석사)-- μ„œμšΈλŒ€ν•™κ΅ λŒ€ν•™μ› : μ˜κ³ΌλŒ€ν•™ μž„μƒμ˜κ³Όν•™κ³Ό, 2019. 2. κΉ€μš©μ§„.μ„œλ‘ : 심방세동 ν™˜μžλ“€μ€ λ‹¨μˆœνžˆ 일반 인ꡬ 집단에 λΉ„ν•΄μ„œ 사망λ₯ μ΄ λ†’λ‹€κ³  μ•Œλ €μ Έ μžˆλ‹€. κ·ΈλŸ¬λ‚˜ λ‚˜μ΄, 성별에 따라 심방세동이 사망λ₯ μ— λ―ΈμΉ˜λŠ” 영ν–₯이 μ–΄λ– ν•œμ§€, 그리고 ꡬ체적인 μ‚¬λ§μ˜ 원인이 무엇인지에 λŒ€ν•œ λŒ€κ·œλͺ¨ 연ꡬ가 거의 μ—†λŠ” 싀정이닀. 방법: κ΅­λ―Όκ±΄κ°•λ³΄ν—˜κ³΅λ‹¨ ν‘œλ³Έ μ½”ν˜ΈνŠΈμ—μ„œ μΆ”μΆœν•œ 15,411λͺ…μ˜ 심방세동 ν™˜μžλ“€μ˜ 사망 원인을 ICD-10 λΆ„λ₯˜ μ²΄κ³„λ‘œ ν™•μΈν•˜μ˜€λ‹€. κ²°κ³Ό: 2002λ…„λΆ€ν„° 2013λ…„κΉŒμ§€ 총 4,479λͺ… (29%)이 μ‚¬λ§ν•˜μ˜€λ‹€. 쑰사망λ₯ μ€ 1천 인년 λ‹Ή 63.3 μ΄μ—ˆλ‹€. 심방세동 ν™˜μžλ“€μ€ 일반 인ꡬ 집단에 λΉ„ν•΄μ„œ 3.7배의 사망 μœ„ν—˜μ„ λ‚˜νƒ€λ‚΄μ—ˆλ‹€. ν‘œμ€€ν™” μ‚¬λ§λΉ„λŠ” μ Šμ€ ν™˜μžμ—μ„œ κ°€μž₯ λ†’μ•˜κ³  λ‚˜μ΄κ°€ λ“€μˆ˜λ‘ 점자 κ°μ†Œν•˜μ˜€λ‹€ (20μ„Έ 미만의 ν‘œμ€€ν™” 사망비 21.93, 95% 신뒰ꡬ간 7.60-26.2680μ„Έ μ΄μƒμ˜ ν‘œμ€€ν™” 사망비 2.77, 95% 신뒰ꡬ간 2.63-2.91). μ—¬μ„± 심방세동 ν™˜μžμ˜ 사망 μœ„ν—˜μ΄ 남성 심방세동 ν™˜μžμ˜ 사망 μœ„ν—˜λ³΄λ‹€ λ†’μ•˜λ‹€ (μ—¬μ„±μ˜ ν‘œμ€€ν™” 사망비 3.81, 95% 신뒰ꡬ간 3.65-3.98λ‚¨μ„±μ˜ ν‘œμ€€ν™” 사망비 3.35, 95% 신뒰ꡬ간 3.21-3.48). 심방세동 ν™˜μžλ“€μ˜ κ°€μž₯ ν”ν•œ 사망 원인은 μ‹¬ν˜ˆκ΄€κ³„μ§ˆν™˜μ΄μ—ˆκ³  (38.5%), λ‡Œκ²½μƒ‰μ΄ κ·Έ μ€‘μ—μ„œλ„ κ°€μž₯ ν”ν•œ μ›μΈμ΄μ—ˆλ‹€. 심방세동 ν™˜μžλ“€μ΄ μ‹¬ν˜ˆκ΄€κ³„ μ§ˆν™˜μœΌλ‘œ 사망할 μœ„ν—˜μ€ 일반 인ꡬ 집단에 λΉ„ν•΄μ„œ 5λ°° κ°€λŸ‰ λ†’μ•˜λ‹€. κ²°λ‘ : 심방세동 ν™˜μžλ“€μ€ 일반 인ꡬ 집단에 λΉ„ν•΄μ„œ 4λ°° κ°€λŸ‰ 사망 μœ„ν—˜μ΄ λ†’μ•˜λ‹€. κ·ΈλŸ¬λ‚˜ 심방세동이 사망에 λ―ΈμΉ˜λŠ” 영ν–₯은 λ‚˜μ΄κ°€ λ“€μˆ˜λ‘ κ°μ†Œν•˜μ˜€κ³ , λ‚¨μ„±μ—μ„œ μ•½ν™”λ˜μ—ˆλ‹€. λ‡Œκ²½μƒ‰μ€ 심방세동 ν™˜μžμ˜ κ°€μž₯ ν”ν•œ 사망 μ›μΈμœΌλ‘œ, λ‡Œκ²½μƒ‰μ˜ μœ„ν—˜μ„ μ€„μ΄λ €λŠ” 좔가적인 λ…Έλ ₯이 ν•„μš”ν•˜κ² λ‹€.Background: Patients with atrial fibrillation (AF) are known to have higher risk of mortality. There is a paucity information regarding the impact of AF on mortality risk stratified by age, sex, and detailed cause of death in a population-based study. Methods: In Korean National Health Insurance Service-National Sample Cohort, 15,411 patients with AF were enrolled, and causes of death were identified according to ICD-10 codes. Results: From 2002 to 2013, a total of 4,479 (29%) deaths were confirmed, and crude mortality rate (MR) for all-cause death was 63.3 per 1,000 patient-years. Patients with AF were at 3.7-fold increased risk of all-cause death compared with general population. Standardized mortality ratio (SMR) for all-cause death was highest in those with young age and attenuated with increasing age [SMR 21.93, 95% confidence interval (CI) 7.60-26.26 in <20 yearsSMR 2.77, 95% CI 2.63-2.91 in β‰₯80 years]. Women with AF exhibited a greater excess mortality risk than men (SMR 3.81, 95% CI 3.65-3.98 in womenSMR 3.35, 95% CI 3.21-3.48 in men). Cardiovascular disease was the leading cause of death (38.5%), and cerebral infarction was the most common specific disease. Patients with AF had about 5 times increased risk of death for cardiovascular disease compared with general population. Conclusions: Patients with AF had 4 times increased risk of mortality compared to general population. However, the impact of AF on mortality attenuated with age, and men. Cerebral infarction was the most common cause of death, and further attention should be made to reduce the risk of stroke.Abstract (Engligh) i Contents iii List of Tables and Figures iv Introduction 1 Materials and Methods 1 Results 7 Discussion 22 Conclusions 26 Reference 28 Abstract (Korean) 35Maste

    Experimental Analysis on Drag Reduction of a Heavy Vehicle Using Various Boat tails

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    DoctorMany attempts have been made to reduce the cost of transportation. Drag reduction of heavy vehicles, such as trucks or tractor-trailers, has significant influence on the reduction of fuel consumption and CO2 emission, because the transport of freight using heavy vehicles largely accounts for the cost of transportation. Thus, improvement of the fuel efficiency of heavy vehicles has been gaining considerable attention. Several aerodynamic flow-control devices, such as cab-roof fairing, side skirts, boat tail, and vortex generators, were introduced to reduce the aerodynamic drag force of heavy vehicles. However, it is still unclear how the unsteady flow around a heavy vehicle influence on the drag force and how to reduce this drag force effectively by adopting flow-control devices. In the present study, drag reduction of a real-shaped 15-ton heavy vehicle model was experimentally investigated by attaching various boat tails as a passive flow-control device attached on the near end of the vehicle. The drag force exerted on the vehicle model was measured by using a 7-component balance. The wind tunnel experiment was conducted at Re = 9.1 Γ— 105, based on the height of the vehicle model. The drag coefficients of the standard vehicle model without flow-control devices were compared with those attached with various boat tails. Furthermore, particle image velocimetry (PIV) measurements were carried out to observe how the flow structures modified by the attachment of various boat tails. In this study, two different type boat tails were proposed to reduce drag and side forces. At first, the modified boat tail with a lower inclined air deflector (LIAD) was investigated as a passive flow-control device attached at the rear end of the heavy vehicle. The aerodynamic performance of the modified boat tail with LIAD was experimentally examined by measuring the drag force, side force exerting on the real-shaped heavy vehicle model with varying yawing angle. As a result, the maximum drag reduction effect of the boat tail with LIAD (Ɵ = 45Β°) is about 9.02%, compared to the standard vehicle without the boat tail, although the length of the bottom tail is half of that of four-way boat tail. This result indicates that the boat tail with LIAD effectively suppresses the formation of large-scale recirculating flow in the wake behind the rear body of the vehicle, due to effectively guide of the underbody flow. Next, a new boat tail was proposed for reducing drag and side forces. The sinusoidal- shaped of the proposed boat tail edge was bio-inspired by the feathers owl flying freely in a variety of environments to improve driving stability under crosswind conditions. The sinusoidal boat tail (SBT) was bio-inspired by the tail shape of the bird’s wings. The bio-inspired SBT was found to have a significant influence on the reducing of drag and sides force and yawing moment under crosswind conditions. At a yaw angle of 7Β°, the drag and side forces are reduced by 15.9% and 22.6%, respectively at maximum, compared to those of the standard vehicle without SBT. The yawing moment coefficient is noticeably decreased by the attachment of SBT. As a conclusive result, the bio-inspired SBT can effectively improve the aerodynamic performance and the driving stability of the vehicle. The PIV velocity field results show that the SBT effectively suppresses the formation of longitudinal vortices by enhancing the streamwise velocity of the wake behind the boat tail. In addition, due to the development of secondary swirling flow, the streamwise momentum deficit is also reduced in the wake region. The boat tails with LIAD and SBT proposed in the present study are found to effectively control the wake behind the vehicle by simple modification of tail shape or additional attachment of a flow-control device on the boat tail. The effective drag-reducing flow-control devices developed for heavy vehicles, would greatly contribute to the world-wide energy saving and reduction of environmental emission

    Quantitative visualization of flow around an autorotation maple samaras

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    Drag reduction of a heavy vehicle using the lower inclined air deflector

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