Predicting Wave-induced Ripple Geometry and Bottom Friction Factor

Nearshore nourishments are a common intervention used to mitigate sediment deficits in coastal areas experiencing erosion problems. This coastal intervention involves placing nourished sediments in the submerged zone of the beach profile to form an artificial submerged sandbar which are then distributed by natural forces occurring in the coastal zone. Coastal processes that control the morphological evolution of coastal zones operate on several spatial and temporal scales (seconds to years) and can be divided into cross-shore and longshore components. Usually, the numerical models that simulate the evolution of cross-shore profiles due to sediment transport within the profiles, are related with short to medium-term events (days to months), and shoreline evolution models, that allow for long-term analysis (years to decades), are typically only considering longshore sediment transport. Describing all the processes in a single numerical model is complex and computationally demanding, and therefore, the numerical models are typically focused on specific processes, categorized by their temporal and spatial scales. This article presents a numerical study focused on medium to long-term numerical modelling of coastal zone evolution, examining the combined effects of cross-shore and longshore sediment transport processes of sediment transport. The model incorporates two simplified numerical models: LTC - Long Term Configuration, for shoreline evolution and CS-Model, for cross-shore sediment exchanges. Applied to nine different sandbar scenarios, model results revealed that disturbances in sandbar volume tend to return to equilibrium through cross-shore sediment transport processes. In situations that considered a constant sandbar volume alongshore, the longshore effects are null, because the volume entering in the coastal domain is equal to the volume leaving, and the sediment balance is only dependent of the cross-shore processes. Variable sandbar volume alongshore leads to impacts on shoreline position due to longshore sediment transport gradients generated by the sandbar disturbance. The results demonstrate the potential of the proposed combined model for medium to long-term projections, allowing for the interpretation of how physical aspects of nearshore nourishments evolve. These aspects include sandbar volume, shoreline position, berm width, and shoreline displacements induced by cross-shore and longshore sediment transport processes. These parameters aid in understanding sandbar-beach sediment dynamics, which is valuable for supporting coastal management, particularly in the development and design of shoreface sand nourishments, enabling the optimization of sand resources.

Entrance/exit losses and cross-sectional stability of double inlet systems

Guo, C.; Guan, X.; Shi, L., and Qiu, S., 2018. The influence of earth pressure balanced shield tunnel underpassing coastal water body on stratum deformation. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 237–246. Coconut Creek (Florida), ISSN 0749-0208. The complexity of construction technology and the surrounding soil environment of shield tunnel, especially the construction of soil pressure balanced shield tunnel in soft foundation, will inevitably cause the settlement of the overlying soil stratum and surface of tunnel. When there is coastal water body on the surface above the tunnel, it will change the distribution and size of pore water pressure in the soil stratum below the coastal water body, thus affecting the settlement of the overlying soil stratum of tunnel. However, most urban subway tunnels are double-tunnel single-track shield tunnels, and successive tunnel construction will also cause the ...

Lian, Y., 2018. Innovative design of marine resources database system based on fuzzy cluster analysis. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 662–667. Coconut Creek (Florida), ISSN 0749-0208.Traditional marine resources database system has performance issue in aspects of CPU, memory, index, therefore, this paper proposes a kind of innovation design method of marine resources database system based on fuzzy clustering analysis. Firstly, on the basis of collecting the marine capture yield over the years, the statistical information of fishing effort data, the biological parameter of main commercial fish and the research literature bibliography of fishery resources, we sort out and add data, and build the innovative database of marine resources, and then use the fuzzy clustering analysis method to realize the function of data processing and analysis. Finally, we use basic language programming to give the software flow chart of system. Experimental result shows that the performance of the proposed method is greatly improved in terms of query response efficiency, actual data warehousing efficiency, and data analysis performance.

Zhang, H., 2018. Multi-point digitalization research of hull plate based on visual communication of hull information. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 685–690. Coconut Creek (Florida), ISSN 0749-0208. The surface of hull plate is mostly composed of complex and inextensible spatial surface. The bending process of it is still finished by hand, which has become one of the bottlenecks in the digitalization of hull construction. In order to realize the digital processing of hull plate, combined with visual communication and according to the requirements of hull plate forming technology, a technical scheme based on PID control method was applied to the hull plate forming. By applying the multi-point forming process, large-scale steel plate was formed in the small equipment. In the multi-point digital forming system, combined with the PID control method, the required shape was obtained through prec...

Chen, C.; Chiang, Z.; Liu, Y., and Zeng, X., 2018. Critical success factors in marine safety management in shipping industry. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 846–850. Coconut Creek (Florida), ISSN0749-0208.About three-fourth of global flow of cargo is currently transported through shipping. The boom of international trade, which mainly depends on marine transportation, in past years has shipping industry become the economic focus in coastal countries. Along with the economic development and increasing global trade, the increasing number of ships and large-scale ships, accidents at sea are not eliminated with improving marine technology. It is therefore important for shipping industry, through management, establishing safety management mechanism conforming to regulations and suitable for ships to reduce operational risks and further eliminate accidents caused by personal factors in order to create business performance of enterprises. Shipping industry is the research object in this study. Supervisors and employees of Fujian Shipping Company are sampled for the questionnaire survey. Total 300 copies of questionnaire are distributed, and 256 valid copies are retrieved, with the retrieval rate 85%. The research results are concluded as followings. (1) From the survey, organizational planning was mostly emphasized in safety management in shipping industry. (2) From the overall weights of evaluation indicators, tope five indicators, among 17 evaluation indicators, are competent personnel, censorship, regulation compliance, sound system, and administrative support. Suggestions are proposed according to the results, expecting to analyze the critical factors in the establishment of safety management systems in shipping industry. Proper strategic suggestions are also proposed to solve the problems encountered in safety management systems to enhance the effectiveness of safety management.

He, N.; Jiang, T., and Zhang, L., 2018. Experimental research on the vapor pressure and critical parameters of ethyl fluoride (HFC-161). In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 129–134. Coconut Creek (Florida), ISSN 0749-0208. Nowadays, many alternative refrigerants are studied for protecting ozonosphere. HFC161 is one of these refrigerants which are friendly to environment, because its Ozone Depleting Potentials (ODP) is zero. And it has a very low global warming potential, high cooling capacity and excellent energy efficiency. In present work, the vapor pressure of HFC161 has been measured using a static type apparatus over the temperature range from 233.15 K to 375.15 K, together with the vapor pressure of isobutane (HC-600a) measured in the temperature range from 275.60 K to 343.16 K for verifying the experimental apparatus. The measured vapor pressure data and those reported by other investiga...

Zhao, X. and Yang, S., 2018. The asymmetric synthesis of furanoseterterpene from marine natural products. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 386–391. Coconut Creek (Florida), ISSN 0749-0208.In this paper, the asymmetric synthesis of furanoseterterpene from marine natural products is studied. In the stereo selective synthesis of 16-deacetoxy-scalarafuran, (+) -scalarolid and the analogues of both, scalareol is as starting material and by eight steps reaction, methyl ent-isocopalate is synthetized; in the synthesis of sesterstatins 4/5 and scalarafuran, methyl ent-isocopalate is as the intermediate, to complete the stereoinversion hydroxyl. The key intermediate, III-25, is obtained by Wittig reaction, and the halogenated furan ring is introduced. The intramolecular reductive Heck reaction is as the key step, to get the natural product sesterstatins 4/5 and scalarafuran; in the synthesis of sesterterpene compounds with furan ring, compound II-16 is as the substrate, and the intermediate IV12 and IV13 can be obtained by four steps reaction; the epoxy compounds are obtained by double bond epoxidation. Experiments show that this method is very versatile and greatly improves the development accuracy of marine products.

Wang, S.; Liu, D., and Wang, Z., 2018. The stability and reliability of the marine anchor rock mass under wave action. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 6–11. Coconut Creek (Florida), ISSN 0749-0208.At present, most of the stability and reliability analysis of the coastal and anchor rocks is based on the genetic algorithm, while there is a problem that the efficiency of analysis is low. In this paper, a steady and reliability analysis method based on the wave action of the equivalent plastic strain is proposed. Firstly, the analysis model is established, and the uniform design method, radial basis neural network technology and maximum entropy principle are combined on this basis to complete the stability and reliability analysis. Experiments show that compared with traditional method, the error between the ultimate bearing capacity and the actual ultimate bearing capacity of the method in this paper is smaller, the stability and reliability analysis of the anchorage rock solid with different water content is more accurate and the effect is better.

You, L.; You, L.; Hu, N.; Yang, L.; Sun, Y., and Song, J., 2018. Influence of straw incineration sediments on heavy metal accumulation in marine organisms. In: Liu, Z.L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 375–379. Coconut Creek (Florida), ISSN 0749-0208. With the development of economy and the progress of agricultural science and technology, the demand of straw as a domestic fuel has been greatly reduced, resulting in the phenomenon of straw burning becoming more and more serious, which brings many problems, such as air pollution, fire, and the aircraft cannot take off normally. In addition, the residue after straw incineration contains a large number of toxic and harmful substances, but people are notcare for it. Some are buried on the spot, which destroying the soil structure and causing a decline in the quality of the farmland; some othersare dumping into the sea, and form the straw incineration sediment...

This paper presents new laboratory data on long-wave (surf-beat) forcing by the random breaking of shorter gravity water waves on a plane beach. The data include incident and outgoing wave amplitudes, together with shoreline oscillation amplitudes at long-wave frequencies, from which the correlation between forced long waves and short-wave groups is examined. A detailed analysis of the cross-shore structure of the long-wave motion is presented, and the observations are critically compared with existing theories for two-dimensional surf-beat generation. The surf beat shows a strong dependency on normalized surf-zone width, consistent with long-wave forcing by a time-varying breakpoint, with little evidence of the release and reflection of incident bound long waves for the random-wave simulations considered. The seaward-propagating long waves show a positive correlation with incident short-wave groups and are linearly dependent on short-wave amplitude. The phase relationship between the incident bound long waves and radiated free long waves is also consistent with breakpoint forcing. In combination with previous work, the present data suggest that the breakpoint variability may be the dominant forcing mechanism during conditions with steep incident short waves.

This study investigates bed load sediment transport dynamics in selected areas of Punatsangchhu River, focusing on rock type identification, their association with topography, grain size distribution, and factors influencing bed load transport rates. 1D numerical sediment transport modeling was also done in HEC-RAS 6.3.1 using the discharge data of four years from 2020 to 2023. Bed load sediment samples were collected from 55 plots laid systematically 500 meters apart along the river. Results reveal Granite as the predominant rock type, reflecting the region's geological complexity shaped by Himalayan tectonics. Significant associations between rock types and topography, particularly for Granite Boulder, highlight the complex interplay of topographic factors shaping sediment distribution. Bed load transport rates vary across sediment roundness and river reach types, with round particles exhibiting higher rates and riffles displaying greater transport than pools. Regression analysis confirms the significant influence of river velocity and bed slope on transport rates, emphasizing the importance of hydraulic factors in sediment transport processes. The output from HEC-RAS revealed the highest sediment concentration in this valley during the late summer months directly aligning with the higher flow in these seasons. During these years, critical bed changes in some of the cross-sections were also observed. RS 12521 has witnessed the highest deposition rate of about 2.5 meters and similarly, RS 7006 has witnessed the highest erosion rate of about 2.3 meters. Likewise, the profile plot of the river reveals a series of erosion and deposition processes during this time window, affecting the riverbed and consequently channel morphology.

The hydrodynamics of turbulent oscillatory flow over a gravel-based irregular rough wall is investigated using laser-Doppler anemometry measurements of velocities in a large oscillatory flow tunnel and direct numerical simulation (DNS) of the Navier–Stokes equations. The same periodic irregular roughness was used for both experiments and DNS. Four flow shapes are investigated: sinusoidal, skewed, asymmetric and combined skewed–asymmetric. The experiments were conducted for target Reynolds numbers (based on the Stokes length and standard deviation of free-stream velocity) of$R_{\delta,\sigma }=800$and$R_{\delta,\sigma }=1549$; DNS was conducted for flows with target$R_{\delta,\sigma }=800$. Boundary layer thickness, bottom phase lead and friction factor are in good agreement with previous studies. For the first time, evidence of Prandtl's secondary flows of the second kind in oscillatory flow is presented. Turbulence structure is visualised using isosurfaces of$\lambda _{2}$(Jeong & HussainJ. Fluid Mech., vol. 285, 1995, pp. 69–94), revealing densely packed structures that grow stronger and weaker in correspondence with the free-stream velocity. Reynolds and dispersive stresses peak just below the highest roughness crest, with dispersive stress vanishing a short distance above the roughness. Bursts of turbulence kinetic energy and wake kinetic energy are generated each flow half-cycle, with variable behaviour depending on flow shape. Non-Gaussian turbulence statistics are observed that originate near the wall, becoming increasingly non-Gaussian far from the wall. Probability density functions of turbulence statistics can be closely approximated by a fourth-order Gram–Charlier distribution at most phases and elevations, though when statistics deviate more strongly from Gaussian, streamwise and wall-normal (spanwise) statistics are better described by a Pearson type IV (VII) distribution.

The low Reynolds number k–ε model is used in some commercial hydrodynamic models to determine boundary layer properties. Such models have been found to produce grid-dependent solutions. A reliable engineering estimate of fundamental boundary layer properties is of utmost importance for practicing engineers. Here, the effect of grid spacing in four different versions of the low Reynolds number k–ε model is studied using direct numerical simulation data of a one-dimensional sinusoidal oscillatory boundary layer. A detailed comparison is made for cross-stream velocities, turbulent kinetic energy, bottom shear stress, friction factor and phase difference. For the present data, the limiting value of the distance to the first grid point from the wall is expressed in terms of Stokes layer thickness. It is observed that, in order to predict the boundary layer properties with reasonable accuracy, the first grid point should be placed at a distance of about 0·02 times the Stokes layer thickness from the wall. The results of the present study may be useful for practicing engineers and researchers in their choice of appropriate grid spacing for low Reynolds number k–ε models.

Protection of gravel-dominated coasts through wave farms: Layout and shoreline evolution