. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. KELP BLADE MOTION AND NUTRIENT FLUX Flat plate. Re = -25 -20 -15 -10 -50 5 10 15 20 25 Angle of Incidence (degrees) Ki|>urr 6. Angle-specific flux from a smooth Hal plate at Re, = 2700. Open circles show the static response of the model; filled circles, the dynamic response. The vertical bars are the standard deviation of measure- ments among se\en cycles, an index of the intensity of turbulent mixing o\er the model. The arrows indicate the order in which angles were achieved during a cycle of pitching. layer adjac
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. KELP BLADE MOTION AND NUTRIENT FLUX Flat plate. Re = -25 -20 -15 -10 -50 5 10 15 20 25 Angle of Incidence (degrees) Ki|>urr 6. Angle-specific flux from a smooth Hal plate at Re, = 2700. Open circles show the static response of the model; filled circles, the dynamic response. The vertical bars are the standard deviation of measure- ments among se\en cycles, an index of the intensity of turbulent mixing o\er the model. The arrows indicate the order in which angles were achieved during a cycle of pitching. layer adjacent to the flux sensor has a relatively low turbu- lence intensity at these angles of incidence. In contrast, fluxes at negative angles of incidence (with the sensor on the leeward face of the plate) are high and associated with relatively high turbulence intensities (evidenced by the large standard deviation among cycles). This turbulence (and the associated high flux) is probably due to the shedding of vortices from the leading edge. Measurements of instantaneous flux to the flat plate dur- ing pitching (tilled circles. Fig. 6) show a different pattern. As pitch angle decreases from its maximum, the dynamic flux remains close to the static flux until the plate is parallel to flow (pitch angle = 0). Whereas the static flux shifts to higher values at negative angles of incidence, the dynamic flux remains low through a considerable angle. The standard deviations associated with these low fluxes are small, indi- cating the lack of substantial turbulence. Only at the ex- treme negative angles used here (about -20°) does the dynamic flux increase to approximate that of the static flux. An increase in standard deviation (evidence of an increase in turbulence) is associated with the increase in flux at large negative angles. This pattern of flux at negative, decreasing pitch angles is probably due to the time required for turbu- lence to be established in the lee of the leading edge
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
