Van Rijn Research Articles

Updated Review of Longshore Sediment Transport: Advantages, Disadvantages, and Comparisons Using a Satellite Image Methodology

This review updates the different categories and formulations of the calculation of longshore sediment transport (LST) and summarizes their advantages and disadvantages. Most of these methodologies require calibration for areas different from those studied by their authors. Thus, a method of validation and calibration is presented here by processing satellite images with CoastSat software (release v 2.7) to determine accretion and erosion volumes. This low-cost methodology was applied to Salaverry Beach (Peru) to compare the results of the different formulations. A range of variation between −96% and +68% was observed concerning the error, with van Rijn’s formula being the most accurate for this particular case.

The distribution of velocity and sediment concentration under currents in coastal seas

A power law velocity profile for engineering application was obtained based on the field data set of flow velocity and sediment concentration in coastal areas of Jinzhou, Nantong, and Zhoushan. Using theoretical analyses, van Rijn's formula for sediment concentration profile was modified. Tests of the new power-law velocity profile and the modified formula of suspended sediment concentration against a large data set were performed. The results show a good fit to the data and that these two formulae could demonstrate the basic principles of vertical distribution of flow velocity and suspended sediment concentration, respectively.

Dune Development Dominates Flow Resistance Increase in a Large Dammed River

AbstractDunes are important for bedload transport in almost all large river systems and exert an important control flow resistance. Investigating dunes is fundamental for simulating discharge, sediment transport, and flood routing. However, the spatiotemporal dynamics of dunes and flow resistance remain poorly understood in large alluvial river systems mainly due to the lack of high‐resolution data. Here we analyzed in‐field observed data on annual profiles of 450 cross‐sections, river bathymetry, discharge, water levels, and sediment in the Middle Yangtze River, and found that dunes developed and flow resistance increased (+10%) in the post‐Three Gorges Dam period. We ascertain that the development of dunes plays the dominant role in augmenting flow resistance, as evidenced by roughness height change (+29%) using a modified Van Rijn method. Ultimately, dune development was incorporated into a hydrogeomorphic numerical model of the Yangtze River to improve flow resistance quantification, and thus, the water level simulation. Our findings highlight the potential increase in flow resistance in response to upstream damming in large rivers and have important implications for flood management and riverine ecology.

X-ray fluorescence analysis in the study of paintings – an overview

Energy dispersive X-ray fluorescence analysis (EDXRF) is an excellent method in investigations of cultural heritage treasures, including easel and wall paintings and illuminations in ancient manuscripts. As one of the few methods applicable for this purpose, it is non-destructive and non-invasive. It is often combined with other methods such as optical microscopy, visible light photography, UV fluorescence photography, infrared reflectography, Fourier transform infrared spectroscopy, X-ray radiography, Raman spectrometry and others. The complex layered structure and mixtures of pigments, especially on easel paintings, represent a challenging task from the point of view of analysis. However, without taking samples it is only possible to analyse the thin surface layer of the investigated object with a thickness of tens to a few hundreds of micrometres. Nevertheless, this is not too much a problem when analysing paintings and even more so in the analysis of illuminations in manuscripts. The paper has an overview character and aims to summarise the possibilities, advantages and problems of XRF in this area and to demonstrate them on selected examples of published works, which in some cases are devoted to the works of leading painters from various historical periods (Giotto di Bondone, Antonello da Messina, Raffaelo Sanzio, Antonio Allegri da Corregio, Anthonis van Dyck, Rembrandt van Rijn, Giorgio Marini, Pablo Picasso and others). This review includes also a brief mention of selected research carried out in our laboratory.

Prediction of Bedform Dimensions on Alluvial Bed in Unidirectional Flow

In this study, the bedform dimensions of an alluvial bed in a unidirectional flow were experimentally investigated. A series of flume experiments was conducted; 700 sets of flume and field data were used in developing formulae for predicting the bedform dimensions on alluvial beds in unidirectional flow. Bedform dimensions include the length and height of bedforms generated by the lower and upper flow regimes; the resistance coefficient for the flow in different flow regimes is introduced into the proposed formulae. The momentum boundary-layer thickness was introduced as an independent variable instead of the flow depth. Based on a large amount of flume and field data, the coefficients of each parameter were determined; four typical formulae were used to compare the accuracy of the proposed formulae. The experimental results show that the momentum boundary-layer thickness, hydraulic radius, and resistance coefficient for the flow in different regimes correlate well with the bedform dimensions. The calculation results show that the dimensionless particle size should not be ignored in the calculation of bedform dimensions. The bedform dimensions have an obvious trend of rapid increase with an increase in the ratio of flow depth to sand size (H/d). The bedform dimensions obtained using the van Rijn method and the Engelund and Hansen method did not represent the variation trend of the bedform length in the upper flow regime with an increase in H/d when H/d was greater than 103. The calculations using the proposed formulae are more accurate and reasonable than those in previous studies predicting the bedform height and length on an alluvial bed in a unidirectional flow.

Order effects in stimulus discrimination challenge established models of comparative judgement: A meta-analytic review of the Type B effect.

This paper provides a comprehensive review of the TypeB effect (TBE), a phenomenon reflected in the observation that discrimination sensitivity varies with the order of stimuli in comparative judgment tasks, such as the two-alternative forced-choice (2AFC) paradigm. Specifically, when the difference threshold is lower (higher) with the constant standard preceding rather than following the variable comparison, one speaks of a negative (positive) TBE. Importantly, prominent psychophysical difference models such as signal detection theory (Green & Swets, 1966) cannot easily account for the TBE, and are hence challenged by it. The present meta-analysis provides substantial evidence for the TBE across various stimulus attributes, suggesting that the TBE is a general feature of discrimination experiments when standard and comparison are presented successively. Thus, inconsistent with psychophysical difference models, subjective differences between stimuli are not merely a function of their physical differences but rather also depend on their temporal order. From the literature, we identify four classes of potential candidate theories explaining the origin of the TBE, namely (1) differential weighting of the stimulus magnitudes at the two positions (e.g., Hellström, Psychological Research, 39, 345-388 1977), (2) internal reference formation (e.g., Dyjas, Bausenhart, & Ulrich, Attention, Perception, & Psychophysics, 74, 1819-1841 2012), (3) Bayesian updating (e.g., de Jong, Akyürek, & van Rijn, Psychonomic Bulletin and Review, 28, 1183-1190 2021), and (4) biased threshold estimation (García-Pérez & Alcalá-Quintana, Attention, Perception & Psychophysics, 72, 1155-1178 2010). As these models, to some extent, make differential predictions about the direction of the TBE, investigating the respective boundary conditions of positive and negative TBEs might be a valuable perspective for diagnostic future research.

Temporal variation of braided intensity and morphodynamic changes in a regulated braided river using 2D modeling and satellite images

AbstractThe river morphology of a braided‐type river is rather complex. High sediment transport rates and frequently changing discharges are the cause of dynamic planform evolution. Over the past few decades, scientific attention has been directed toward understanding the coexistence of alternating bars and the consequent emergence of confluences and divergences, all of which interact intricately with the process of bank erosion. It is still rather challenging to estimate or predict the total sediment transport rate in this type of river, especially by considering various hydrologic data and climate effects. This study is focused on the reach of the Devoll River in Albania, located upstream of the Banja dam. Understanding the morphodynamics of this river reach holds significance due to the expanding delta upstream of the dam reservoir. The objectives of the two‐dimensional depth‐averaged approach of the present study are to investigate the temporal variation of braided intensity of Devoll River and the effect of using a discharge hydrograph from hydrologic data compared to the regulated one from the upstream dam on the morphodynamics and sediment transport of the river. After evaluating various parameters such as 11 different sediment transport functions, the best results were reached for a cell size of 5 × 5 m2, Manning roughness coefficient of 0.03, Meyer‐Peter and Müller's sediment function, Hayashi et al. (1980) hiding function, and Van Rijn bed roughness predictor in this study. In addition, the results of comparing satellite images and modeling the river from 2019 to 2023 show that the braided index decreased, and this can be due to the fact that the real scenario of the river has a regulated discharge compared to the non‐regulated discharge from hydrologic data, in the mentioned period.

About the Alkemade Theorem and the Limits of its Applicability for the Construction of Ternary Liquidus Surfaces

The Alkemade theorem goes back to a very fundamental paper on the graphical description of thermodynamic equilibrium problems from 1893 (van Rijn van Alkemade in Z Phys Chem 11: 289-327, 1893). It is one of the most helpful implements for the construction of the liquidus surface of ternary phase diagrams. In its original form, it allows to find the direction of falling or increasing temperature along the monovariant reaction lines forming the boundaries of the primary crystallization fields. The theorem is valid for systems with any number of phases; however, its geometrical construction rule is only defined for the case of stoichiometric phases and it is not clear how to apply the theorem in the case of phases with extended homogeneity ranges. Some examples from a ternary, transition-metal-based system containing phases with large homogeneity ranges are presented, and the usefulness and limits of applicability of the theorem are discussed.

Aristotle’s Difference

This essay revisits one of the most acclaimed paintings of Rembrandt van Rijn’s later years, Aristotle with the Bust of Homer (1654; The Metropolitan Museum of Art). The painter’s approach to the subject of this work owes much to visual precedents and to the reception of Aristotle among early modern men of letters, including within the intellectual circles of seventeenth-century Holland. The unusual appearance of the philosopher, which has often led to conflicting interpretations, becomes much clearer when considered against the long-standing perception of his cultural “otherness.” The stance and gesture of this Aristotle not only affirm his identity but point to key aspects of his epistemology, focusing on the role of touch as the first step toward knowledge.

Sediment transport modelling upstream of Al Kufa Barrage

Abstract This study estimated the amount of bed sediment load upstream of Kufa Barrage mainly depending on the hydrodynamic conditions, sediment concentration, and hydraulic parameters. Ten cross-sections approximately over 2 km in length in front of the barrage were selected. Velocities and suspended sediment concentrations at 0.2, 0.6, and 0.8 of the water depth at each section were recorded using an ADCP device. A depth-integrated sampling was utilized to examine the collected data from 6th January to 15th October 2022. It was noted that the effective depth-to-width computation methods and the Toffaleti sediment transport function with the Van Rijn fall velocity were the most compatible and appropriate approaches for determining the sediment transport potential in the selected reach. It was also noted that such techniques were better than the previous formulae to predict the total sediment load. The results revealed excellent agreement between the mean sediment discharge obtained using HEC-RAS 6.2, equal to 6.214 kg/s, and the mean sediment discharge obtained from the field measurements, equivalent to 7.142 kg/s.

Using automatic model calibration for 3D morphological simulations: a case study of the Bodendorf reservoir flushing

AbstractReservoir sedimentation poses a significant challenge to water resource management. Improving the lifespan and productivity of reservoirs requires appropriate sediment management strategies, among which flushing operations have become more prevalent in practice. Numerical modeling offers a cost-effective approach to assessing the performance of different flushing operations. However, calibrating highly parametrized morphological models remains a complex task due to inherent uncertainties associated with sediment transport processes and model parameters. Traditional calibration methods require laborious manual adjustments and expert knowledge, hindering calibration accuracy and efficiency and becoming impractical when dealing with several uncertain parameters. A solution is to use optimization techniques that enable an objective evaluation of the model behavior by expediting the calibration procedure and reducing the issue of subjectivity. In this paper, we investigate bed level changes as a result of a flushing event in the Bodendorf reservoir in Austria by using a three-dimensional numerical model coupled with an optimization algorithm for automatic calibration. Three different sediment transport formulae (Meyer-Peter and Müller, van Rijn, and Wu) are employed and modified during the calibration, along with the roughness parameter, active layer thickness, volume fraction of sediments in bed, and the hiding-exposure parameter. The simulated bed levels compared to the measurements are assessed by several statistical metrics in different cross-sections. According to the goodness-of-fit indicators, the models using the formulae of van Rijn and Wu outperform the model calculated by the Meyer-Peter and Müller formula regarding bed patterns and the volume of flushed sediments.

Numerical investigation of dam break flow over erodible beds with diverse substrate level variations

Abstract This study aimed to comprehensively investigate the influence of substrate level difference and material composition on dam break wave evolution over two different erodible beds. Utilizing the Volume of Fluid (VOF) method, we tracked free surface advection and reproduced wave evolution using experimental data from the literature. For model validation, a comprehensive sensitivity analysis encompassed mesh resolution, turbulence simulation methods, and bed load transport equations. The implementation of Large Eddy Simulation (LES), non-equilibrium sediment flux, and van Rijn’s (1984) bed load formula yielded higher accuracy compared to alternative approaches. The findings emphasize the significant effect of substrate level difference and material composition on dam break morphodynamic characteristics. Decreasing substrate level disparity led to reduced flow velocity, wavefront progression, free surface height, substrate erosion, and other pertinent parameters. Initial air entrapment proved substantial at the wavefront, illustrating pronounced air-water interaction along the bottom interface. The Shields parameter experienced a one-third reduction as substrate level difference quadrupled, with the highest near-bed concentration observed at the wavefront. This research provides fresh insights into the complex interplay of factors governing dam break wave propagation and morphological changes, advancing our comprehension of this intricate phenomenon.

Fetch‐driven aeolian sediment transport on a sandy beach: A new study

AbstractThis study examines the effect of fetch distance on aeolian sediment transport and the corresponding growth rate of aeolian transport rate on a sandy beach under varying wind speeds. Eight experiments were conducted on both dry and intertidal beach areas, with wind speeds ranging from 9 to 17 m/s. Vertically stacked sand traps were used to measure transport rates over distances up to 100 m, with experiments lasting 20–40 minutes. Results indicate an initial increase in transport rate until the critical fetch distance, followed by a subsequent decrease in sediment transport with further fetch distance. Critical fetch distances, corresponding to maximum transport rates, ranged from 23.8 to 103.5 m. A strong linear correlation was observed between wind speed and critical fetch distance, suggesting that higher wind speeds necessitate longer fetch distances for maximum transport. Furthermore, established formulations by van Rijn and Strypsteen are tested to estimate maximum sediment transport and critical fetch distance based on grain‐related shear velocity. Combining all experiments showed that the growth rate in transport up to the point of critical fetch can be best described by a trigonometric function. These findings contribute to a better understanding of the fetch effect on aeolian sediment dynamics in coastal sandy environments.

Study and Evaluation of Solid Discharge for the Design of Hydraulic Structures for Road Interception: LAHJAR River Site, High Atlas, Morocco

Because of the global warming, the phenomenon of Solid Transport (bedloading transport and suspension transport), have increasingly serious impact on the normal function of hydraulic road drainage in the Higt atlas Morrocco. Indeed, they are clogged even if they are recently built, which generates the submersion and flooding of neighboring areas. This causes enormous material damage and threatens the safety of local residents.\nSo, in this work, we studied and quantified the solid flow as part as the design of hydraulic structure \" drain \" on flow crossing the Provincial Road RP 2010 in the “LAHJAR River Site” in the High Atlas Morrocco. The area study is located in the “Ourika” watershed. It is also called “LAHJAR” because il carries lot of pebbles each time the flood passes.\nWe tested the most widely used calculation methods worldwide in this study. After checking the field results (the 100-year solid deposition height at the structure = 1.5 m), we found that: \n- the formulas of Van Rijn, Engelund Hansen, Rickenmann gives values negligible. \n- the values from the formulas of Meyer Peter and Müeller, Watanabe, Ribberink, and Parker, are comparable to those observed.\n- the formulas of Schoklitsch and Sogreah, give excessive results.\nThus, this heigt of solid deposit is also important that liquid and must be considered in the design study.

Investigation of uniform and graded sediment wash-off in an urban drainage system: Numerical model validation from a rainfall simulator in an experimental facility

Understanding sediment wash-off in urban environments plays an essential role in sediment transport management; and is critical for accurate pluvial flood control to assist in adaptation and mitigation strategies. Sediment transport models have been researched previously, though challenges still arise due to the complicated nature of graded sediment transport. This study tested the accuracy of the van Rijn model using a sparse distribution of particle sizes using the geometric mean. As such, this study used high-resolution datasets collected in a water laboratory to investigate sediment wash-off and transport on an urban street. This included the interaction of two gully pots receiving sediment loads that were washed off from a hypothetical urban surface by three rainfall intensities. The results showed that the model was able to simulate uniform sediments entering the gully pots accurately when the sediment size was assigned to a median diameter. Using the grain diameter to represent the geometric mean can improve the model performance for simulating a graded sediment.

The importance of grain‐related shear velocity in predicting multi‐monthly dune growth

AbstractThis study assesses the accuracy of the aeolian transport model proposed by van Rijn and Strypsteen in 2020 in predicting sediment transport rates for dune growth, with a focus on the importance of grain‐related shear velocity. A 9‐month dataset of local and regional wind characteristics and dune growth from a new artificial dune with planted marram grass in an environment with minor supply limitations was analysed. The study site is located in Oosteroever, Belgium. The results revealed that utilizing local measured overall shear velocities resulted in significant overprediction of dune volume changes. Incorporating sub‐models for grain‐related bed roughness and shear velocity improved the predictions of dune growth drastically with high statistical results (r2 = 0.98 and RMSE = 0.64 m3/m). The primary driver contributing to dune growth at the study site was due to oblique onshore moderate winds of 10 m/s, as revealed from a frequency‐magnitude analysis. The model could be used with either local wind measurements or regional data transformed to local beach conditions. The study highlights the importance of considering grain‐related shear velocity in future studies to improve the prediction of sand transport rates and enhance our understanding of dune evolution.

APPLICATION OF CROSS-SHORE MORPHOLOGICAL MODELS FOR PERCHED BEACHES

Perched beaches are beaches that are supported at the offshore side by a submerged structure. The advantages of such design schemes are that less dredged material is required, and more protected waters are created in front of the beach. Apart from the hydraulic stability of the submerged structure itself, the stability of the beach needs to be studied in order to make sure it fulfils the requirements during its design lifetime. Aspects that play a role here are the expected sand losses over the submerged structure, the (dynamic) equilibrium profile of the beach and the performance during storm conditions. In order to study the morphological responses of such beaches, morphological models should be applied that can take into account the influence of the submerged structure. This paper discusses two cross-shore models that have been used to study a large perched beach project that is under construction in unusually deep waters, severe wave climate (mostly unidirectional) and small tidal range. The models applied are SBEACH (Larson et al., 1989) and CROSMOR (Van Rijn et al., 2003). First the models are validated and calibrated hydrodynamically by comparing the wave transmission and wave setup with measurements from 2D flume tests. Next, the models have been used to predict the future cross-shore development of the beach.

Field Measurements of Longshore Sediment Transport along Denu Beach, Volta Region, Ghana

Field measurements of longshore sediment transport have been performed in the surf zone along Denu Beach, located in the Volta Region of Ghana, West Africa. This study consisted of measuring sediment transport rates by the deployment of modified versions of Kraus streamer traps on a cross-shore distance, which was about half the average surf zone width. In addition to the measured transport rates, data on waves, longshore currents, and other morphological parameters were collected with simple and low-cost instrumentation. In total, about 22 datasets were obtained through several days of data collection spanning a period of 5 months. Mathematical formulae proposed by CERC (1984), Kamphuis (1991), and the new van Rijn (2014) were used to compute theoretical transports for the entire surf zone, which were validated by measured data. Applying the CERC equation with a K-value of 0.39, the theoretical transports were about one order of magnitude higher than the measured rates. The rates computed by the Kamphuis formula were slightly higher than those yielded by the van Rijn equation. They produced values that were, on average, about 3.5 and 2.9 times higher than the measured rates, respectively. This study then confirmed the capabilities of both the Kamphuis and van Rijn equations to provide closer estimates of longshore sediment transport on Denu Beach. It especially sheds light on the new van Rijn formula, which has not been used extensively in LST quantification across the world. We, therefore, concluded that both the Kamphuis and van Rijn equations could be particularly useful to local engineers in the prediction of LST prior to the design of coastal protection structures. Further long-term studies employing available cutting-edge technologies were also recommended to provide more information on longshore transport not only in Ghana but also in the entire Gulf of Guinea and for the establishment of a reliable sediment budget for the country and the entire region.

In-situ characterisation of fluvial dune morphology and dynamics under limited sediment supply conditions, Seine River, France

Dune dynamics and associated sedimentary fluxes have been estimated over a period of a week in the river Seine characterised by limited sediment supply. Distributed into two corridors, typical medium and small dunes associated with fluvial environments have been characterised from multibeam data acquired on four dates, 23-29 March 2021, after a limited peak flood. Dune morphometric parameters have been quantified on cross-dune 1 m spacing of bed elevation profiles and dune migration rates have been calculated by analysing successive multibeam acquisitions. Evidence of limited sediment supply conditions have been recognised from areas uncovered by mobile sediment in the troughs between medium dunes. Under such conditions, bedload transport associated with dune migration has been estimated using three methods: differential bathymetry, dune tracking and the Van Rijn empirical formula using a correction factor accounting for limited sediment supply conditions. The three methods provide similar bedload fluxes (less than an order of magnitude difference), and the small differences are related to input data uncertainties and the capability of these methods to capture sediment transport processes, such as sediment bypassing dunes. Based on field observations, this paper brings new constrains to the relationships between dune morphological parameters, migration rates and sedimentary fluxes and environmental parameters (sediment grain size, flow velocity and water depth) under limited supply conditions in a real river.

Numerical modeling of scour and erosion processes around spur dike

AbstractSpur dikes are popular river training structures used for flow diversion, flood control, bank protection, and improving navigation. This paper aims to study the numerical modeling of scour depth in the vicinity of a rectangular spur dike using the renormalization group (RNG) turbulence model and sedimentary van Rijn model with nested mesh configuration using FLOW‐3D. This study is also carried out to analyze the three turbulence models such as RNG, 𝑘−𝜀, and Large‐Eddy simulation (LES), for estimating the scour depth and evaluating the temporal variation of maximum scour depth. It is observed that scour depth is overpredicted with the LES model configuration used in the present study, as compared to 𝑘−𝜀 and RNG models. Furthermore, the scour depth increases by increasing the bed load coefficient near to the spur dike. Simulated results show a good agreement within a 5% error with experimental results regarding the net change of sediment elevation and scour depth.