• 캠버 ν•­λ ₯ (Camber Drag)

    calendar Mar 20, 2020 Β· 1 min read Β· drag  Β·
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    캠버항λ ₯은 μ—μ–΄ν¬μΌμ˜ 캠버와 λ‚ κ°œμ˜ λΉ„ν‹€λ¦Ό 각에 μ˜ν•΄μ„œ μœ λ°œλ˜λŠ” ν•­λ ₯이며 μ•„λž˜μ™€ 같이 ν‘œν˜„ν•  수 μžˆλ‹€. $$C_{D_{camber}} = \frac{e}{1-e} K (\Delta C_{L}^{2})$$ μ—¬κΈ°μ„œ eλŠ” 슀팬 νš¨μœ¨κ³„μˆ˜μ΄λ©° KλŠ” μœ λ„ν•­λ ₯ λΉ„λ‘€μƒμˆ˜, $\Delta C_{L}$은 캠버에 μ˜ν•œ μ–‘λ ₯ 증가뢄이며 μ•„λž˜μ™€ κ°™λ‹€. $$\Delta C_{L} = \left( 1-\frac{1}{\pi \cdot A \cdot K} \right) C_{Lopt}$$ μ—¬κΈ°μ„œ $C_{Lopt}$λŠ” 일반적인 μ—μ–΄ν¬μΌμ˜ κ²½μš°μ— λ‹€μŒκ³Ό κ°™λ‹€. $$C_{Lopt} = 0.8505 …


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  • μœ λ„ν•­λ ₯ (Induced Drag)

    calendar Mar 19, 2020 Β· 1 min read Β· drag  Β·
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    μœ λ„ν•­λ ₯은 λ‚ κ°œμ—μ„œ μ–‘λ ₯이 λ°œμƒν•˜λ©΄ ν•„μ—°μ μœΌλ‘œ λ°œμƒν•˜λŠ” λ‚ κ°œ 끝 와λ₯˜μ— μ˜ν•œ ν•­λ ₯으둜 μ–‘λ ₯κ³„μˆ˜μ˜ μ œκ³±μ— λΉ„λ‘€ν•œλ‹€. $$C_{D_{i}} = KC^{2}_{L}$$ μ—¬κΈ°μ„œ λΉ„λ‘€μƒμˆ˜ KλŠ” Oswald 슀팬 νš¨μœ¨κ³„μˆ˜λ²•(Oswald Span Efficiency Method)κ³Ό μ•žμ „ ν‘μž…λ²•(Leading Edge Suction Method) 두 가지 λ°©λ²•μœΌλ‘œ ꡬ할 수 μžˆλ‹€. Oswald 슀팬 νš¨μœ¨κ³„μ‚°λ²• μ•„μŒμ† ν•­κ³΅κΈ°μ˜ 경우, νƒ€μ›ν˜• μ–‘λ ₯뢄포λ₯Ό κ°–λŠ” λ‚ κ°œμ™€ λΉ„κ΅ν•œ 효율(e)에 μ˜ν•΄μ„œ K 값이 κ²°μ •λœλ‹€. $$K=\frac{1}{\pi e A}$$ μ—¬κΈ°μ„œ μŠ€νŒ¬νš¨μœ¨κ³„μˆ˜ e …


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  • μœ ν•΄ν•­λ ₯ (Parasite Drag)

    calendar Mar 18, 2020 Β· 4 min read Β· drag  Β·
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    μœ ν•΄ν•­λ ₯은 μ–‘λ ₯κ³Ό λ…λ¦½μ μœΌλ‘œ λ°œμƒν•˜λŠ” ν•­λ ₯이며 λ§ˆμ°°ν•­λ ₯(frictio Drag), ν˜•μƒν•­λ ₯(Form Drag), μ••λ ₯ν•­λ ₯(Pressure Drag), κ°„μ„­ν•­λ ₯(Interference Drag) λ˜λŠ” μ‘°νŒŒν•­λ ₯(Wave Drag) 등이 이에 ν•΄λ‹Ήν•œλ‹€. $$C_{D_{p}}=\Sigma(C_{f_{c}} \cdot FF_{c} \cdot Q_{c} \cdot S_{wet_{c}})\frac{1}{S_{ref}} + C_{D_{wave}} + C_{D_{base}} + C_{D_{misc}}$$ μ—¬κΈ°μ„œ $C_{f}$λŠ” ν‰νŒμ˜ λ§ˆμ°°ν•­λ ₯κ³„μˆ˜(Flat Plate Skin …


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