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The Pearl River Estuary is a typical estuary region in southern China, and the study of surface wave occurrence and characteristics is of great importance for shipping management, nearshore engineering, and monitoring shoreline changes and other human activities. Long-term and continuous observational data are critical for achieving a better understanding of waves. In this study, the wave measurements based on a high-precision wave gauge were analyzed and observation data over approximately two years at a sampling frequency of 2 Hz were obtained. The wave system in the Pearl River Estuary was found to deviate from the assumption of a stationary stochastic process similar to that in the open ocean, due to the effects of abnormal waves caused by human activities. Therefore, traditional distribution functions such as Rayleigh and Weibull were not suitable for accurately fitting the main wave parameters ( H s , T p , etc.), particularly in the tail. Consequently, abnormal wave signals were extracted from all wave sets, and through the comparison and analysis of the wave spectral features, it was determined that these abnormal waves are caused by the ship wakes. The spectral characterization of these waves was performed to determine the characteristics of different ship wake processes. Ship wakes in the Pearl River Estuary are an important part of the wave system, and their wave height is significantly larger than the normal wave. Based on the spectral characteristics of ship wakes, this study proposed some news characteristics of ship wakes in the main channel of the Pearl River Estuary. [ABSTRACT FROM AUTHOR]

We aim to perform a series of field measurements for high-speed railway tunnels in China to obtain the micropressure wave (MPW) at the tunnel exit and the transient pressures near the tunnel portals. The relationship between the MPW and the nose-entry wave and the effects of train speed and the tunnel exit hole on the MPW are analyzed. The results show that the MPW decreases with increasing distance from the tunnel exit, but increases rapidly with increasing train speeds. Additionally, holes in the hoods near the tunnel exit could decrease the MPW near the tunnel exit by 10-20%. [ABSTRACT FROM AUTHOR]

ABSTRACT You, Z.J.; Ji, Z.Z., and Bai, Y.Z., 2018. Impacts of storm wave-induced coastal hazards on the coast of China. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 826–830. Coconut Creek (Florida), ISSN 0749-0208. The mainland coast of China is 18,000km long and houses more than 50% of its population. There are increasing pressures to develop the Chinese coastal areas for residential, commercial, tourism and recreational purposes. However, the coast of China has been periodically ravaged by tropical cyclones, storm surges and large coastal waves, resulting in heavy losses of coastal economy and human lives. Three individual extreme tropical cyclones occurred in 1956, 1969 and 1994, for example, resulted in the total losses of more than 7,400 human lives and enormous economic damage. The most recent data show that the coastal natural hazards on the coast of China have resulted in annual damage of about US $3 billion to the coastal economy and annual loss of 256 human lives. Few researchers in China have quantitatively assessed impacts of storm waves and high wave runup on the coast of China. This study is designated to quantitatively assess impacts of storm wave-induced coastal hazards on the coast of China based on the most recent coastal hazard data (1989–2016). It is found that the combination of storm-induced high surges and large waves is responsible for all major coastal natural hazards and especially for heavy losses of human lives on the coast of China, and that the storm wave-induced hazard intensity increases spatially from the north to south along the coast and well correlates to wave energy flux. [ABSTRACT FROM AUTHOR]

The beach-bar reservoir has become an important exploration target in China, but its depositional mechanism and controlling factors have not yet been fully modeled. They have become an inhibitory factor for the exploration and development of beach-bar reservoirs. The depositional mechanism of beach-bars and their controlling factors have been studied by means of a flume experiment including seven runs under controlled boundary conditions which were the water level (Run 1, Run 2 and Run 3), wave parameters (Run 1, Run 4 and Run 5) and initial slope (Run 1, Run 6 and Run 7). The experiment revealed that the development of beach-bar was controlled by water level, wave parameters and initial slope. The deposited locations of distal bar and nearshore bar were controlled by the water level. Two beach-bars were migrated downward when the water level falls (Run 1, Run 2 and Run 3). The width and thickness of distal bar and nearshore bar were controlled by wave parameters, especially the wave height. They increased with the scale of wave. But, the maximum thickness is limited by the water level (Run 1, Run 4 and Run 5). The distance between distal bar and nearshore bar was controlled by the initial slope. It became shorter with the steeper slope. Distal bar and nearshore bar changed into one bar when the initial gradient was greater than 1/20 (Run 1, Run 6 and Run 7). The results suggest formative mechanism and controlling factors related to beach-bars. [ABSTRACT FROM AUTHOR]

This paper discusses how the literature was created based on the experiences of the "Educated Youth" in the reform and opening-up era. Firstly, the author summarizes the network and literary activities of the Educated Youth. Second, he analyzes the poetry of literary magazines that they expressed their own experiences in the reform era, and thirdly, he discusses the trial by the magazine's editorial staff to describe their experiences in fiction and its difficulties. Furthermore, this paper examines the origin of Chinese literature on 1980s, especially the origin of modernism literature in China. [ABSTRACT FROM AUTHOR]

• The morphology resistance to waves of invasive S.alterniflora is higher than native P.australis. • P. australis allocate excessive energy during stem growth, thereby decreasing reproduction and fitness. • Economic energy allocation contributed to the successful invasion of S. alterniflora. Smooth cordgrass (Spartina alterniflora) introduced to China in 1970 s for coastline stabilization threatening the habitat range of native Phragmites australis and even become more adaptive than P. australis. Thus, we used electronic universal testing machine and Van Soest method to compare the morphological and biomechanical responses of these two species to wave interference in the Yellow River Delta, east China. Our study showed that the morphological response of P. australis was more sensitive to waves with shorter individuals in wave zones but larger stem diameter and higher biomass than those in none-wave zones, while S. alterniflora did not exhibit such variations. In wave zones, S. alterniflora invaded P. australis ' habitat regardless higher stem-bending resistance of P. australis with excessive energy allocated in stem growth while decreasing reproduction and fitness. Compared with the none-wave zones, S. alterniflora allocated excessive energy in the stem to resist wind interference, and they are less fitted than P. australis. Thus, economic energy allocation to wave mechanical interference contributed to the successful invasion of S. alterniflora to landward in estuaries. S. alterniflora continued to expand landward in a semi-saline area but the community pattern may maintain the status quo for areas with low salinity and high wave interference. [ABSTRACT FROM AUTHOR]

Kuang, C.; He, L.; Gu, J.; Pan, Y.; Zhang, Y.; Yang, Y.; Qiu, R., and Zhang, J., 2014. Effects of submerged breakwater on hydrodynamics and shoreline change of the East Beach of Beidaihe, Bohai Bay, China. The beaches in Beidaihe of Bohai Bay of China have been eroded since 1950s, clearly evidenced by sand coarsening, rock outcropping, and slope steepening. Beach nourishment is a common coastal management strategy used to protect beaches from erosion along sandy coastlines, and it has already been applied to recover several beaches of Beidaihe since 2008. In this paper, the effects of a submerged breakwater used as part of a beach nourishment project on hydrodynamics and shoreline changes of the East Beach of Beidaihe are presented. First, the brief descriptions of phase I and phase II of the beach nourishment project of East Beach are given. And then numerical models, including tidal current model, wave model, and one-line model for simulating hydrodynamics (tidal currents and waves) and shoreline changes are established and verified by field measurements. These well-verified numerical models are adopted to compute the tidal current fields, wave fields, and shoreline changes of East Beach with and without the submerged breakwater. The results show that the submerged breakwater plays a very important role in protecting East Beach to a certain degree. The effects of alterations of the freeboard and the width and the length of the submerged breakwater on shoreline changes are also discussed, and the results show that increasing the above three parameters will better protect the beach. Overall, a submerged breakwater can play a certain role in protecting a beach against erosion; additional beach nourishment is needed to stabilize East Beach in long term. [ABSTRACT FROM AUTHOR]

We measured the in situ suspended sediment concentration (SSC) and hydrodynamics (waves, currents, and sea level) concurrently during a storm event using self-recording instruments at offshore of the Shandong Peninsula in the Yellow Sea. We analyzed the temporal variation in suspended sediment carrying capacity and its correlation with wave, current, and water-level conditions. There was about 40% increase in SSC during the storm event. A 3-4-h lag was observed between the peak of wave height and SSC. The SSC increased in a fluctuating pattern up to the peak then decreased rapidly. This process was positively correlated with wave height and duration. The maximum SSC was 524.3 mg/l, which is about 10 times of that under normal weather conditions. This peak was observed after of a series of 1.8 m waves. The increased suspended sediments were the fine particles resuspended by the storm waves from seabed near the observation spot and transported by northward ebb currents from Shidao Bay. [ABSTRACT FROM AUTHOR]

ABSTRACT: The effects of waves on Surface Drag Coefficient (SDC) and surface mixing length were analyzed and discussed by carrying out three-dimensional current modeling for the Bohai Sea in the present work. A three-dimensional coupled hydrodynamical-ecological model for regional and shelf seas (COHERENS) incorporating the influences of wave-current interactions was coupled with the third-generation wave model swan taking into account time-varying currents. The effects of waves on currents were included in the SDC, surface mixing length and bottom drag coefficient. Firstly, the formulations in Donelan were incorporated into the COHERENS to account for wave-dependent SDC. In order to compare simulation results for the wave-dependent SDC, the simulation for wind-dependent SDC was also carried out. Second, Wave-Induced Surface Mixing Length (described as WISML sometimes in this paper) was incorporated into the COHERENS. Four numerical experiments were conducted to discuss the effects of two kinds of wave processes. Generally, the values of time series of current velocity and water surface elevation given by the simulation with all of the three wave processes have a good agreement with observed data. The existence of WISML changes obviously current vertical profiles and the existence of the wave dependent SDC modifies the current field of both top and bottom layers with the wind-dependent SDC. [Copyright &y& Elsevier]

This work investigates the dynamic behaviors of floating structures with moorings using open-source software for smoothed particle hydrodynamics. DualSPHysics permits us to use graphics processing units to recreate designs that include complex calculations at high resolution with reasonable computational time. A free damped oscillation was simulated, and its results were compared with theoretical data to validate the numerical model developed. The simulated three degrees of freedom (3-DoF) (surge, heave, and pitch) of a rectangular floating box have excellent consistency with experimental data. MoorDyn was coupled with DualSPHysics to include a mooring simulation. Finally, we modelled and simulated a real mariculture platform on the coast of China. We simulated the 3-DoF of this mariculture platform under a typical annual wave and a Typhoon Dujuan wave. The motion was light and gentle under the typical annual wave but vigorous under the Typhoon Dujuan wave. Experiments at different tidal water levels revealed an earlier motion response and smaller motion range during the high tide. The results reveal that DualSPHysics combined with MoorDyn is an adaptive scheme to simulate a coupled fluid–solid–mooring system. This work provides support to disaster warning, emergency evacuation, and proper engineering design. [ABSTRACT FROM AUTHOR]

Knowledge about the tradeoffs among turbulent kinetic energy (TKE), waves, and suspended sediment concentrations (SSCs) in the nearshore zone is relevant for understanding beach morphodynamics at different temporal and spatial scales. A field measurement lasting for nearly three tidal cycles was conducted to holistically discern couplings between TKE, waves and SSCs, with further evaluation of the relative significance of TKE and waves on SSCs under various wave conditions over a meso-macro tidal beach, Yintan, to the north of Beibu Gulf, China. The results showed a dramatic increase in wave groupiness intensity from the shoaling wave condition to the breaking wave condition and a clear decrease further into the surf bore condition. The near-bed TKEs under the surf bore condition were an order of magnitude larger than those under the breaking and shoaling wave conditions at the measurement position. The averaged SSCs in the near-bed (approximately 10 cm) under the surf bore condition were 1.5 and 4.5 times larger than those under breaking and shoaling wave conditions, respectively. The variations in relative wave height were a decisive indicator for the differences in TKE intensities among different wave conditions, while the occurrence of peak TKEs at the wave front within the intrawave cycle was associated with flow acceleration regardless of wave conditions. Mean SSCs were well correlated with waves in terms of both incident wave scale and wave group scale, which was limited to the shoaling wave condition, and the occurrence of near-bed intrawave peak SSCs was always related to the offshore wave phase. Further, TKE contributed more effectively to sediment suspension at the wave group scale than at the incident wave scale, especially under broken wave condition. Among the hydrodynamic factors, TKE played the most important role in the variations in SSCs for all wave conditions. Flow acceleration served as the second most important factor under the broken wave condition, while wave group, single wave and advection were equivalent and less important factors for SSCs. Unlabelled Image • Variation in relative wave height was a decisive indicator of TKE intensity. • The occurrence of near-bed peak SSCs was related to offshore wave phase. • Correlated TKE events occupying 12.2% of total time produce 42.9% of SSC events. • TKE played the most important role in variations of SSC time series. [ABSTRACT FROM AUTHOR]

Wind-induced hydrodynamics are important forcing mechanisms of sediment resuspension in lakes. However, the relative contributions of wind-induced waves and currents on sediment resuspension during a wind event remain unclear. This study used high-frequency sensors to investigate the effects of wind waves, lake currents, and shear stress on sediment resuspension under different wind conditions (10 September to 17 October 2017) in Lake Taihu (China). Measurements showed that wind speed varied from 0.3 to 11.5 m/s, wave height varied from 0.035 to 0.46 m, lake current speed ranged from 0.001 to 0.39 m/s, and turbidity changed from 36.5 to 158.7 NTU. Sediment resuspension resulted primarily from wave- and current-induced shear stresses. Calculation showed these quantities varied in the range 0.045-0.338 and 0.002-0.127 N/m 2 , respectively. Total shear stress showed positive correlation with turbidity. Wave-induced shear stress contributed more than 60% of the total. Waves and currents have different responses to wind. During periods of increasing turbidity, the percentage of wave-induced shear stress was initially high (> 85%) before decreasing with the development of the current. During periods of decreasing turbidity, the percentage of wave-derived shear stress declined initially before increasing with the decrease of current speed. The results showed a clear process regarding the contributions of shear stress from waves and currents during different stages of hydrodynamic development, which could be used to describe sediment resuspension in large shallow lakes that would help in the development of high-efficiency sediment resuspension models.