Browsing by Author "Department of Civil Engineering, Colorado State University, publisher"
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Item Open Access A study of D.A.F. Darrieus vertical axis wind turbine at the C.S.U. Dairy Farm: final report(Colorado State University. Libraries, 1980-07) Abarikwu, Okezie Ibeji, author; Meroney, Robert N., author; Department of Civil Engineering, Colorado State University, publisherItem Open Access A study of wind effects on Houston twin office buildings(Colorado State University. Libraries, 1972-09) Peterka, J. A., author; Cermak, J. E., author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Aerodynamics: a time dependent flow model for the inner region of a turbulent boundary layer(Colorado State University. Libraries, 1981-04) Chien, Ho-Chen, author; Sandborn, Virgil A., author; Department of Civil Engineering, Colorado State University, publisherResponse of the flow variables to external driving forces is non-linear for shear flows. For the turbulent boundary layer case, surface shear stress fluctuations of magnitude as great as the mean value are observed. For flow near the surface Prandtl's turbulent boundary layer approach of employing averaged Reynolds equation and a turbulence closure model is insufficient to account for surf ace shear fluctuations. A model which incorporates a discrete time dependent solution for the inner region of the turbulent boundary layer is proposed. The model requires stochastic averaging of the time dependent solution to account for the random aspect of the flow. The physical model for the flow near the surface is based on the bursting cycle observed in the inner region of a turbulent boundary layer. Localized pressure gradients created in the valleys of the large scale structures of the outer region of the flow are assumed to be the origin of the bursting process. This model treats the sweep motion as an impulsively started flow over a flat plate. An averaging technique is demonstrated to predict the important features of the surface shear stress. In order to confirm the time dependent model assumptions, measurements of the probability distribution and cross-correlation of the longitudinal turbulent velocity and the surface shear stress were evaluated. The sweep-scale, sweep-direction, and origin of the instability are determined from isocorrelation maps. The shape of the probability density distributions of the velocity near the surface and the surface shear stress are found to be similar. However, the velocity probability distribution changes rapidly with increasing distance from the surface. As implied by the time dependent model for the surface shear stress, the magnitude of the large surface shear stress would be substantially changed if the sweep motion could be modified. A series of thin, metal plates were employed to block the instability from reaching the surface. Results show that the mean value of surface shear and the large magnitude fluctuations of surface shear stress were reduced significantly. The variation in surface shear was found to be extremely sensitive to slight angle of attacks of the plates.Item Open Access Aerodynamics: control of surface shear stress fluctuations in turbulent boundary layers(Colorado State University. Libraries, 1981) Sandborn, Virgil A., author; Department of Civil Engineering, Colorado State University, publisherItem Open Access An iIllustrative environmental assessment: the Cameron Pass highway improvement(Colorado State University. Libraries, 1976-10) Hendricks, David W., author; Vlachos, Evan, author; Bluestein, Mark Herman, author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Analysis of hydraulic geometry relationships in alluvial channels(Colorado State University. Libraries, 1984-04) Julien, Pierre Y., author; Simons, Daryl B., author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Calculator program and nomograph for on-site prediction of ephemeral gully erosion(Colorado State University. Libraries, 1985-02) Thorne, Colin R., author; Zevenbergen, Lyle W., author; Grissinger, Earl H., author; Murphey, Joseph B., author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Control of combined sewer overflows in Minneapolis-Saint Paul(Colorado State University. Libraries, 1971-10) Tucker, L. Scott, author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Correlation analysis of unit hydrograph, storm and watershed parameters: a status report(Colorado State University. Libraries, 1973-08) Schulz, Edmund F., author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Data evaluation for Yazoo Basin Study(Colorado State University. Libraries, 1978-06) Simons, D. B., author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Deriving a unit hydrograph in the absence of detailed rainfall data(Colorado State University. Libraries, 1973-06) Ragavendran, R., author; Schulz, Edmund F., author; Jawed, Khalid, author; Department of Civil Engineering, Colorado State University, publisherA method of deriving a unit hydrograph from two different recorded flood events from the same watershed was tested. The method was originally proposed by De Laine. This technique was tested on floods recorded on a 1.07 square mile watershed in Arizona, on floods simulated on the 1/2 acre Experimental Rainfall-Runoff Facility at Colorado State University and finally on flood simulated on a 40 acre hypothetical watershed. It was found that De Laine's method is practical only on error-free data. If there is any error in the determination of the rainfall excess, or in the measurement of runoff or in the synchronization of rainfall and runoff records, the solution becomes unstable. The method produced unsatisfactory results for the Safford, Arizona and the CSU-ERRF data.Item Open Access Design of small water storage and erosion control dams(Colorado State University. Libraries, 1975) Wood, Alan Douglas, author; Richardson, E. V. (Everett V.), 1924-, author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Diffusion from a continuous point source into the boundary layer downstream from a model hill: technical report(Colorado State University. Libraries, 1965) Plate, Erich J., author; Sheih, C. M., author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Effect of sediment on resistance to flow in cobble and boulder bed rivers(Colorado State University. Libraries, 1978-05) Simons, Daryl B., author; Li, Ruh Ming, author; Al-Shaikh-Ali, Khalid Saddiq, author; Department of Civil Engineering, Colorado State University, publisherField and experimental evidence are presented to demonstrate the importance of the inflow of sand and gravel size sediments, released under extreme floods from watersheds and banks of streams, on resistance to flow in channels whose beds are formed of large size roughness elements such as cobbles, rocks and boulders. The released sediments fill the spacings between the large size roughness elements, and may inundate them completely, forcing the channel to behave as a sand bed channel at a much reduced resistance to flow coefficient. Under extreme conditions resistance to flow in these channels decrease to more than one-third its original value resulting in an underestimations of the following quantities: water discharge by a factor of two, sediment discharge by a factor ranging between 8 and 64, velocity of flow by a factor of two. Furthermore, an overestimation of flow depth by a factor of two can result. Impacts of failure to estimate the previous quantities with a reasonable degree of accuracy are: underestimation of the actual quantity of available water, improper selection of bank protection material, overestimation of reservoir life, unsafe design of scour depths at hydraulic structures, improper design of highway location as well as others relating to river control and development.Item Open Access Essays on river mechanics(Colorado State University. Libraries, 1988-05) Julien, Pierre Y., author; Saghafian, Bahram, author; Lips, Elliott W., author; Anthony, Deborah, author; Wargadalam, Jayamurni, author; Zahoor, Tabassum, author; Wassum, Rob, author; Chen, Yi-Ching, author; Bennett, Brian M., author; Arthur, Basil K., author; Waddle, Terry, author; Choi, Gye Woon, author; Santoro, Vincenza Cinzia, author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Essays on river mechanics(Colorado State University. Libraries, 1995-04) Wilkerson, Gregory V., author; Noss, Darcy K., author; Dudley, Syndi J., author; Fischenich, J. Craig, author; Carroll, John M., author; Landers, Mark N., author; Sunantara, Judith D., author; Lewis, Todd M., author; Cluer, Brian L., author; Meier, Claudio I., author; Kuriowa, Julio M., author; Wick, Edmund J., author; Julien, Pierre Y., author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Essays on river mechanics(Colorado State University. Libraries, 1996-04) Johnson, Billy E., author; Delcau, Mitchell R., author; Guo, Junke, author; Eldaw, Ahmed Khalid, author; Molnár, Peter, author; Wilson, James M., author; Mishra, Su K., author; Cueto, Maria, author; Julien, Pierre Y., author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Essays on river mechanics(Colorado State University. Libraries, 1993-04) Peters, Mitch, author; Gessler, Dan, author; Arneson, L. A., author; Noshi, Hani M., author; G., Lilian Posada, author; Fotherby, Lisa M., author; James, Ed, author; Julien, Pierre Y., author; Department of Civil Engineering, Colorado State University, publisherItem Open Access Essays on river mechanics(Colorado State University. Libraries, 1987-05) Julien, Pierre Y., author; Department of Civil Engineering, Colorado State University, publisherPresented by the Graduate Students in CE 717 River Mechanics (Spring 1987).Item Open Access Filtration of Giardia cysts and other substances. Volume 3, Rapid rate filtration(Colorado State University. Libraries, 1985-02) Logsdon, Gary S., author; Al-Ani, Mohammad, author; McElroy, John M., author; Hibler, Charles P., author; Hendricks, David W., author; Department of Civil Engineering, Colorado State University, publisherThe efficiency of rapid rate filtration for removal of .Giardia lamblia cysts, standard plate count bacteria, total coliform bacteria, and turbidity was determined experimentally under a wide range of operating conditions. Percent removals were evaluated by means of a lab-scale pilot plant at temperatures of 4°C and 18°C, for low turbidity water, at hydraulic loading rates of 8 cm/min (2 gpm/ft2, 24 cm/min (5 gpm/ft2) and 33 cm/min (8 gpm/ft2), for "in-line" filtration, for three filter media, and using three chemicals. Testing was performed also using a 1.3 L/s (20 gpm) field-scale rapid rate filtration pilot plant. The range of testing was narrower and focused on ascertaining the findings at the lab-scale. The study has shown, that rapid rate filtration is a highly efficient treatment process for low turbidity waters when proper chemical pretreatment is used. Certain polymers, such as Magnifloc 572C® or Magnifloc 573C® in conjunction with alum will effectively coagulate low turbidity, low temperature water, i.e. when raw water turbidity level is less than 1 NTU, and when temperature is 0-4°C. Lab-scale results, for example, showed that using 5 mg/L of alum as Al2(SO4)3.14H20 followed by 1.5 mg/L Magnifloc 572C, Giardia cyst removals were 99 percent, and standard plate count bacteria and total coliform bacteria removals were greater than 99 percent. At the same time, corresponding turbidity removals of about 80 percent were obtained using raw water having less than 1 NTU turbidity. With no chemical pretreatment, removals of all substances, including Giardia cysts, ranged from only 10 percent to 70 percent. The results showed that rapid rate filtration will effectively treat low turbidity water, and will removal Giardia cysts if proper chemical pretreatment is used. Proper chemical pretreatment is difficult to determine and to evaluate for low turbidity waters since the usual measures of effectiveness such as turbidity removals and coliform bacteria removals are based upon very low amounts in the raw water. Pilot plant testing is imperative to ascertain proper chemical pretreatment, when using low turbidity waters. It covers the period March 1, 1981 to February 28, 1984, and work was completed as of February 28, 1984.