Numerical simulation is very useful for understanding the hydraulic fracturing mechanism. In this paper, we simulate the hydraulic fracturing using the distinct element approach, to investigate the effect of some critical parameters on hydraulic fracturing characteristics. The breakdown pressure obtained by the distinct element approach is consistent with the analytical solution. This indicates...

In this paper the control problem of a hydraulic servo-system is addressed. The performance achievable by classical linear controllers, e.g. PD, are usually limited due to highly nonlinear behavior of the hydraulic dynamics. This paper adopts the backstepping design strategy to develop a Lyapunov-based nonlinear controller for a hydraulic servo-system. Load, hydraulic and valve dynamics are inc...

Recently, a benchmarking test study of several hydraulic river models has been undertaken by the authors ^. One of the tests being investigated was the performance of hydraulic river models in using measured and interpolated crosssections for unsteady flows. Details of the interpolation algorithm for obtaining interpolated cross-sections are described in the paper. It is shown that the appropri...

Hydraulic bending roll system has become one of key equipments to control the exit strip shape in strip rolling mills. The hydraulic bending roll system of a hot rolling mill was researched and analyzed, and its mathematics models were founded in whole based on the action principle of some representative hydraulic components. At last, the hydraulic bending roll system was simulated with MATLAB ...

Hydraulic conductivity is commonly estimated from grain size characteristics of unconsolidated sediments. We present an extensive set of air-permeability and grain size measurements from a heterogeneous aquifer. These data are unique in that the hydraulic conductivity measurements are made on undisturbed in-situ sediment and, like the grain size measurements, have a small sample volume size (<1...

A model that relates hydraulic permeability to water flux and to gradients in pressure potential and solute potential was tested using soybean (Glycine max) plants. Water flux was varied by additions of polyethylene glycol 6,000 around one portion of a divided root system and by changing the light intensity and CO(2) concentration around the plants. The data are compatible with the model only i...

Simulation techniques to reduce the fuel consumption in hydraulic excavators are presented in three categories: first, a strongly non-linear dynamic simulation technique for a coupling system with a non-linear hydraulic system and a linkage system; second, a technique for evaluating fuel consumption in the engine when the engine powers the hydraulic pump in a digging operation performed by a hy...

-A free-surface flow can change from a supercritical to subcritical flow with a strong dissipative phenomenon called a hydraulic jump. Herein the progress and development in turbulent hydraulic jumps are reviewed with a focus on hydraulic jumps operating at large Reynolds numbers typically encountered in natural streams and hydraulic structures. The key features of the turbulent hydraulic jumps...

Power system performance is affected by dynamic characteristics of hydraulic governor-turbines during and following any disturbance, such as occurrence of a fault, loss of a transmission line or a rapid change of load. Accurate modelling of hydraulic governor-turbines is essential to characterise and diagnose the system response during an emergency. In this article, both detailed and simplified...

A better understanding of the mechanistic basis of stomatal control is necessary to understand why modes of stomatal response differ among individual trees, and to improve the theoretical foundation for predictive models and manipulative experiments. Current understanding of the mechanistic basis of stomatal control is reviewed here and discussed in relation to the plant hydraulic system. Analy...