Buoyant Jet Discharges into Finite Ambient Waters

The paper presents the results of an experimental study regarding the effect of the lateral dimension of the receiving water on the spreading, mixing, and temperature decay of a horizontal buoyant surface jet. The widths of the ambient water in the experiments have been 240, 120, 90 and 60 times the diameter of the jet nozzle. Based on the experimental data, correlations are carried out and empirical equations for prediction of jet width, thickness in vertical direction and longitudinal temperature decay are obtained. The available data of earlier investigators are included to obtain generalized equations for the spreading and temperature decay. Similarity of temperature profiles in the lateral and vertical directions is observed. The longitudinal temperature decay is found to vary inversely with distance in the flow direction and ¼th power of the densimetric Froude number.

Parametric Study of Flood Wave Propagation

A parametric study of the flood wave propagation problem is made, based on numerical solution of the nondimensionalized unsteady flow equations of open channels. The propagation of a sinusoidal flood wave in a prismatic channel is studied for uniform initial flow. The governing parameters (initial uniform flow Froude number, wave amplitude, wave duration, channel width parameter and side slope) are varied over a wide range. In all, 49 cases are studied. Effects of these governing parameters on the subsidence of stage and discharge and the speed of the wave peak are described in detail. The relative wave amplitude is found to vary linearly with F0, the initial uniform flow froude number, for lower F0 values. Wave duration has a very pronounced effect on subsidence with greater subsidence at lower wave duration values.

Characteristics of Proportional Weirs

A theorem termed the Geometrical Continuity Theorem is enunciated and proven. This theorem throws light on the aspects of the continuity of the proportional portion with the base weir portion. These two portions constitute the profile of a proportional weir. A weir of this type with circular bottom is designed. The theorem is used to establish the continuity at the junction of the proportional and the base weir portions of this weir. The coordinates of the weir profile are obtained by numerical methods and are furnished in tabular form for ready use by designers. The discharge passing through the weir is a linear function of the head. The verification of the assumed linear discharge-head relation is furnished for one of the three weirs with which experiments were conducted. The coefficient of discharge for this typical weir is found to be a constant with a value of 0.59.

Proportional Weirs as Velocity Controlling Devices

Of the many factors that govern the settling phenomenon, the flow velocity in the settling tanks can be controlled favorably by fixing suitably designed weirs at the outlets of the tanks. The velocity at the bottom should not dislodge the particles that have already settled. These requirements might be met with by velocities which are controlled to be constant with respect to the depth of flow, or velocities which reduce linearly with increasing depth or velocities that vary inversely with the depth. To achieve these types of velocity control, new proportional weirs have been designed. Very near to the outlet of the tank, over a small length, the flow was found to be turbulent and noncompliant with the expected type of velocity control. This small length of the disturbance may be provided over and above the theoretical settling length of the tank, for efficient sedimentation.

Modified Proportional V-Notch Weirs

Seven different shaped modified proportional V-notches were designed and pertinent data for their use are given in tables 1 - 4. It is shown that the indication accuracies of these weirs are more than that of the conventional V-notch. For five of the designed weirs the indication accuracies are more than that of the conventional rectangular weir at lower heads of flow. All these proportional weirs, except the parabolic based weir, have added advantages over the V-notch in regard to fixing and finding the crest level. Experiments with five weirs (four symmetrical and one unsymmetrical) having rectangular bases and one (symmetrical) with a parabolic base show very good agreement with the theory and give consistent values for the coefficient of discharge, Cd, varying between 0.588 and 0.605, within the ranges of the experiments.

Coupled Solution for Forced Recharge in Confined Aquifers

Analytical solutions for forced well recharge currently in use were initially developed for pumping scenarios and applied for recharge cases assuming that radial flow in the recharge well replicates a mirror image of that in to a pumping well. Moreover these solutions were not extended to multiaquifer systems. Well bore numerical solutions were generally not considering the effect of well bore interaction, which has a significant effect in the case of a recharge well. In the present paper, improved analytical solutions are developed for a well fully penetrating either single or multiaquifers in respect.to of well storage, well loss, and interactions between the individual aquifers through well bore. The solution developed for constant and variable rates of injection and well loss is applied to the experimental data of the Hansol well injection project near the city of Ahmedabad in the Gujarat state in India. The paper also discusses the difference in well hydraulics of recharge and recovery wells.

Design of Constant Accuracy Linear Proportional Weir

Five different shaped weirs were designed and pertinent data for their use are given. One of these weir shapes had the least “sharp edge” at the junction of the base weir and “complementary weir.” Two other types of weirs had equal slopes at the junction of the base weir and complementary weir. Another shape, for which neither the indication accuracy was constant nor the slope was equal at the junction of the base weir and complementary weir, was also tested. The results of the four weir shapes hydraulically tested give consistent values for the coefficient of discharge varying between 0.625 to 0.631. The indication accuracies of all the previously designed linear proportional weirs (includig Sutro weir) are neither constant nor unity, as is believed.