Effect of roughness on sequent depth in hydraulic jumps over rough bed

Vodni skok je značajna pojava karakteristična za otvorene tokove kao što su rijeke i preljevi. Vodni se skokovi uglavnom koriste za raspršivanje kinetičke energije na nizvodnoj strani preljeva i to uz pomoć skretnih blokova. Pokazalo se da je rasap energije mnogo djelotvorniji kada se umjesto glatkog korita koristi hrapavo korito. U ovom se radu prikazuje eksperimentalno istraživanje koje ocjenjuje utjecaj drobljenog kamenog materijala na vodni skok. U istraživanju je korišteno pet serija drobljenog kamena definiranih prema veličini kamena. Rezultati pokazuju da se utjecaj hrapavog korita ne povećava nakon određene visine kamene obloge.Hydraulic jump is an important phenomenon in open channel flows such as rivers and spillways. Hydraulic jump is mainly used for kinetic energy dissipation at the downstream side of a spillway with the assist of baffle blocks. It has been demonstrated that corrugated or rough beds show considerably more energy dissipation than smooth beds. The experimental research evaluating the effect of crushed stones on the hydraulic jump is presented in this paper. Five different-size sets of crushed stones were used. Results show that the effect of rough bed does not increase after a certain height of crushed stone is reached

Large-scale dynamics have greater role than thermodynamics in driving precipitation extremes over India

The changing characteristics of precipitation extremes under global warming have recently received tremendous attention, yet the mechanisms are still insufficiently understood. The present study attempts to understand these processes over India by separating the ‘dynamic’ and ‘thermodynamic’ components of precipitation extremes using a suite of observed and reanalysis datasets. The former is mainly due to changes in atmospheric motion, while the latter is driven mainly by the changes associated with atmospheric moisture content. Limited studies have attributed dynamic and thermodynamic contributions to precipitation extremes, and their primary focus has been on the horizontal atmospheric motion component of the water budget. Our study, on the other hand, implements the decomposition of vertical atmospheric motion, based on the framework proposed by Oueslati et al. (Sci Rep 9: 2859, 2019), which has often been overlooked, especially for India. With the focus on two major and recent extreme events in the Kerala and Uttarakhand regions of India, we show that the vertical atmospheric motion has a more significant contribution to the events than the horizontal atmospheric motion. Further, decomposition of the vertical atmospheric motion shows that the dynamic component overwhelms the thermodynamic component’s contribution to these extreme events, which is found to be negligible. Using a threshold method to define extreme rainfall, we further extended our work to all India, and the results were consistent with those of the two considered events. Finally, we evaluate the contributions from the recently made available CMIP6 climate models, and the results are interestingly in alignment with the observations. The outcomes of this study will play a critical role in the proper prediction of rainfall extremes, whose value to climate adaptation can hardly be overemphasised