Figure 1
(a) Illustration of boundary layer heights in terms of different roughness scales (b) Power spectra depicting turbulent kinetic energy in large eddy scales, production, inertial and viscous dissipation range (Mikkelsen et al., 2017MIKKELSEN, T.; LARSEN, S.E.; JORGENSEN, H.E.; ASTRUP, P.; LARSEN, X.G. Scaling of turbulence spectra measured in strong shear flow near the earth’s surface. Royal Swedish Academy of Sciences, v. 92, n. 12, p. 1-27, 2017.) (c) Atmospheric turbulence and its evolution showing the damping nature of eddy size by means of length scales (Adapted from (Chaudhary and Abhilash, 2012CHAUDHARY, V.; ABHILASH, A. Literature review: Mitigation of atmospheric turbulence on long distance imaging system with various methods. International Journal of Science and Research, v. 3, n. 12, p. 2227-2231, 2012.)).
Figure 2
Comparison of computed time series of Longitudinal wind speed, (U+u) m/s at severe turbulence levels (50%) for a mean wind speed of 12 m/s in MATLAB 2019 software (a) using Von Karmal (1948) and Kaimal (1972)KAIMAL, J.C.; WYNGAARD, J.C.; IZUMI, Y.; COTE, O.R. Spectral characteristics of surface layer turbulence, Q.J.R. Meteorological, Society, v. 98, n. 417, p. 563-589, 1972. model (b) results of Shigeo and Metwally (2018)SHIGEO, Y.; METWALLY, I. Study of turbulence intensity effect on the fatigue lifetime of wind turbines, Evergreen joint. Journal of Novel Carbon Resource Sciences & Green Asia Strategy, v. 5, n. 1, p. 25-32, 2018. using Von Karman and Kaimal model at 50% turbulence intensity.
Figure 3
Comparison of computed time series of Longitudinal wind speed, (U+u) m/s at three different turbulence intensities, low (1%), medium (10%) and severe turbulence levels (50%) for a mean wind speed of 12 m/s (a) using Von Karman (1948)VON KARMAN, T. Progress in structural theory of turbulence. Proceedings of the National Academy of Science,v. 34, n. 11, p. 530-539, 1948. model (b) Kaimal (1972)KAIMAL, J.C.; WYNGAARD, J.C.; IZUMI, Y.; COTE, O.R. Spectral characteristics of surface layer turbulence, Q.J.R. Meteorological, Society, v. 98, n. 417, p. 563-589, 1972. model (c) results of Shigeo and Metwally (2018)SHIGEO, Y.; METWALLY, I. Study of turbulence intensity effect on the fatigue lifetime of wind turbines, Evergreen joint. Journal of Novel Carbon Resource Sciences & Green Asia Strategy, v. 5, n. 1, p. 25-32, 2018. using Von Karman (1948)VON KARMAN, T. Progress in structural theory of turbulence. Proceedings of the National Academy of Science,v. 34, n. 11, p. 530-539, 1948. model at 1% and 50% turbulence intensities.
Figure 4
One-minute time history of longitudinal wind speed, (U+u), lateral and vertical velocity components at 10% turbulence intensity, for mean wind speed of 12 m/s simulated in MATLAB 2019 using
Eq. (15) to
Eq. (17).
Figure 5
(a) Gust factor at different turbulence intensities and gust duration (b) Gust factor as function of height for wind speeds of 5 m/s, 10 m/s 15 m/s and 20 m/s.
Figure 6
Normalized velocity component spectra,
u, v, w and cross spectra,
u-w, functions, for
z = 10 m and U = 20 m/s given by (a)
Eq.(18) to
Eq.(21) (b)
Eq. (22) to
Eq. (25).
Figure 7
(a) Normalized empirical turbulence spectra for different integral length scales at a z0 value of 0.05 m, at U = 50 m/s (b) Comparison of Davenport (1961)DAVENPORT, A.G. The spectrum of horizontal gushiness near the ground in high winds. Journal of Royal Meteorological Society, v. 87, n. 372, p. 194-211, 1961. wind codes adopted by China and Canada, Harris (1971)HARRIS, R.I. The nature of wind, The modern design of wind sensitive structures. Proceedings of CIRIA Seminar, England, p. 29-55, 1971., Simiu (1974)SIMIU, E. Wind spectra and dynamic along wind response. Journal of the Structural Division, v. 100, n. 9, p. 897-191, 1974. wind codes by ESDU (1985) with Kolmogorov’s 5/3rd law at U = 50 m/s.
Figure 8
Normalized (a) longitudinal IEC Kaimal wind spectra at different roughness heights at U = 50 m/s (b) IEC Kaimal standard coherence function along longitudinal direction, at U = 50 m/s, standard roughness z0 = 0.05 m, separation distance, horizontal Δy = 1 m, vertical Δz = 1 m.
Figure 9
Comparison of (a) IEC (1999) coherence function at z = 0.1 m and 25 m for 0.01 Hz using Kaimal (1972)KAIMAL, J.C.; WYNGAARD, J.C.; IZUMI, Y.; COTE, O.R. Spectral characteristics of surface layer turbulence, Q.J.R. Meteorological, Society, v. 98, n. 417, p. 563-589, 1972. spectrum (b) Coherence function at z = 0.1 m , 25 m for 0.01 Hz using Solari (1987)SOLARI, G. Turbulence modeling for gust loading. Journal of Structural Engineering, v. 113, n. 7, p. 1550-1569, 1987. decay parameter at gust wind speed of 70 m/s.
Figure 10
Illustration of (a) longitudinal (
Iu), lateral (
Iv) and vertical (
Iw) turbulence intensities according to ESDU (1985), standard for
z0 value of 0.05 m (b) ESDU (1985) length scales for
z0 value of 0.05 m respectively at 26.91
o north latitude (c) Elevation map of Jaisalmer site in Rajasthan with a mean elevation of 223 m (Source:
www.floodmap.net).
Figure 11
Contour plot of normalized longitudinal wind spectra using IEC Kaimal method at different roughness heights (a) for free stream velocity of 10 m/s (b) for free stream velocity of 15 m/s at separation distance, Δy = 1 m, Δz = 1 m, standard roughness, z0 = 0.05 m.
Figure 12
Contour plot of normalized coherence function for longitudinal wind using IEC Kaimal method at different roughness heights above ground (a) for free stream velocity of 10 m/s (b) for free stream velocity of 15 m/s at lateral separation distance, Δy = 1 m, Δz = 1 m, standard roughness, z0 = 0.05 m.