Resistance to flow in sand channels

CER65EVR27.June, 1965.Includes bibliographical references (pages 77-81).In partial fulfillment of the requirements for the Degree of Doctor of Philosophy in Civil Engineering.A theoretical and laboratory investigation was made of resistance to flow in sand-bed channels. The objectives were to determine the type of flow and energy dissipation in sand-bed channels and develop equations and relations for predicting resistance to flow and mean velocity. The types of flow, energy dissipation and, thus resistance to flow in sand-bed channels is extremely variable because (1) the configuration of the boundary, (2) the properties of the fluid, and (3) the characteristics of the turbulence are functions of the flow, fluid, and sand characteristics and of the geometry of the channel. The boundary configurations that form in a sand bed are ripples, ripples on dunes, dunes, plane bed, antidunes or chutes-and-pools. The type of flow in a sand channel with constant discharge and average energy gradient may be steady or unsteady and uniform or nonuniform, depending on the boundary configuration. With the array of boundary configurations found in sand channels, the dissipation of energy may result from grain roughness, form roughness, acceleration of the flow, breaking waves or any combinations of them. With variable boundary configuration, type of flow and energy dissipation, it is impossible to determine a general equation to predict resistance to flow and mean velocity for all flow conditions. However, if the boundary configuration is known, specific relations and equations are developed for predicting resistance to flow. For steady uniform flow, the equations are based on integrating the Reynolds equation for turbulent flow. The coefficients in the integrated equation were determined from a study of the velocity distribution and verified using the mean flow variables. For nonuniform and (or) unsteady flow, resistance to flow is determined by applying a correction term to the equation developed for flow over a plane bed. The correction term compensates for the increase in energy dissipation resulting from form roughness, flow acceleration and breaking waves. The study of the velocity profiles for plane bed flow when there is considerable bed-material movement, determined that there is an inner and outer flow zone. In the inner zone, the slope A and intercept B in the relation u = A ln y + B are variable. The variation of the slope and intercept are functions of the size and concentration of suspended sediment in the inner zone. In the outer zone , the slope and intercept are constant

Hydraulic model studies

CER62EVR18.Series statement and numbering from publisher's list.Includes bibliographical references (page 13).Stage-discharge relations for two artificial controls were determined in a model study conducted at Colorado State University. The controls are used to measure the discharge at two gaging stations (Cibecue Ridge No. 1 and Cibecue Ridge No. 2), that form a part of an intensive hydrologic investigation of the semi-arid environment of Central Arizona. The gaging stations are located in a remote area where the runoff is infrequent and of brief duration. The model studies were conducted because it was virtually impossible to calibrate the controls in the field. In addition to determining the stage-discharge relation, modifications in the controls are proposed to improve the discharge records for the two stations. A hydraulic jump occurs in the present controls at the section where the stage is measured. The hydraulic jump keeps the controls clear of the large sediment discharge of the streams, but causes large fluctuations of the water surface in the stilling wells. The modified controls eliminate the hydraulic jump, make extensive use of the construction that presently exists, will pass the sediment discharge of the streams, and have a fairly sensitive stage-discharge relation. The recorded elevation of the water surf ace in the stilling well lags the actual elevation of the stream because the connection between the control and the stilling well is too small in relation to the size of the stilling well. The lag can be decreased by replacing the present stilling well with a tube 14 to 20 inches in diameter

Economic value of sediment discharge data

April 1974.Bibliography: pages 37-38.Financially supported by the Colorado State University Experiment Station

Stream gaging control structure for the Rio Grande conveyance channel near Bernardo, New Mexico

CER61EVR42.June 1961.Includes bibliographical references (page 23)

Dye dilution method of discharge measurement

January 1971.CER70-71WSL-EVR47.Includes bibliographical references.Council of U.S. Universities for Soil and Water Development in Arid and Sub-humid Areas.Prepared under support of United States Agency for International Development, AID/csd-2162, Water management research in arid and sub-humid lands of the less developed countries

Resistance to flow in alluvial channels

CER61DBS79.Includes bibliographical references.From: Transactions of the American Society of Civil Engineers, 1962

Mechanics of soil erosion from overland flow generated by simulated rainfall

September 1973.Bibliography: pages 53-54

Forms of bed roughness in alluvial channels

CER60DBS3.January 1960.Includes bibliographical references

Resistance to flow in alluvial channels

CER59DBS48.November 1959.Includes bibliographical references.Presented at the New York ASCE Convention, October, 1958.This paper presents the initial results of a flume study of alluvial channels currently being conducted by the U.S. Geological Survey at Colorado State University. A detailed classification of the regimes of flow, the forms of bed roughness, and the basic concepts pertaining to resistance to now are discussed

Study of flow in alluvial channels: depth-discharge relations, A

CER59DBS34.Includes bibliographical references (page 42).Alluvial channel stage-discharge and depth-discharge relations were studied in a large sand bed-recirculating flume. From this study, it was found that the form of these relationships are intimately related to: 1. Regime of flow; 2. Form of bed roughness, a. Characteristics of the bed material, b. Concentration of fine sediment, c. Temperature; 3. Rate of change of discharge with time. In the range of shear where ripples and dunes develop on the bed, the stage-discharge curve for a rising stage is usually quite different from that for a falling stage. These curves are only valid for the conditions upon which they are based--no general solution is possible. In the range of shear, which develops plane bed, standing sand, and water waves, which are in phase, and antidunes, the rising and falling stage curves coincide and hold for all values of discharge associated with these forms of bed roughness. When a channel experiences a shear stress, which develops dunes at small discharges and plane bed and perhaps standing waves and antidunes at larger discharges, there is a discontinuity in the stage-discharge or depth-discharge curves particularly on the rising stage, which occurs when the dunes wash out. This is caused by the large reduction in resistance to flow, which occurs when the bed form changes from ripples or dunes to plane bed, standing waves, or antidunes, and the resultant reduction in depth even though discharge is increasing