"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates"
"uuid:0b870201-4ae5-41c7-972b-21feb937f657","http://resolver.tudelft.nl/uuid:0b870201-4ae5-41c7-972b-21feb937f657","Modelling Vertical Variation of Turbulent Flow Across a Surf Zone Using SWASH","Zijlema, M.","","2014","This paper presents the application of the open source non-hydrostatic wave-flow model SWASH to propagation of irregular waves in a barred surf zone, and the model results are discussed by comparing against an extensive laboratory data set. This study focus not only on wave transformation in the surf zone, but also on the numerical prediction of undertow and vertical distribution of turbulence levels under broken waves. Present simulations demonstrate the overall predictive capabilities of the model in computing breaking surf zone waves.","surf zone; wave breaking; undertow; turbulence; modelling; SWASH; ICCE 2014","en","conference paper","Coastal Engineering Research Council","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:2a71de36-6ce8-447b-b031-5ba4eb877422","http://resolver.tudelft.nl/uuid:2a71de36-6ce8-447b-b031-5ba4eb877422","Modeling the interaction between flow and highly flexible aquatic vegetation","Dijkstra, J.T.; Uittenbogaard, R.E.","","2010","Aquatic vegetation has an important role in estuaries and rivers by acting as bed stabilizer, filter, food source and nursing area. However, macrophyte populations worldwide are under high anthropogenic pressure. Protection and restoration efforts will benefit from more insight into the interaction between vegetation, currents, waves and sediment transport. Most aquatic plants are very flexible, implying that their shape and hence their drag and turbulence production depend on the flow conditions. We have developed a numerical simulation model that describes this dynamic interaction between very flexible vegetation and a time-varying flow, using the seagrass Zostera marina as an example. The model consists of two parts: an existing 1DV k-? turbulence model simulating the flow combined with a new model simulating the bending of the plants, based on a force balance that takes account of both vegetation position and buoyancy. We validated this model using observations of positions of flexible plastic strips and of the forces they are subjected to, as well as hydrodynamic measurements. The model predicts important properties like the forces on plants, flow velocity profiles and turbulence characteristics well. Although the validation data are limited, the results are sufficiently encouraging to consider our model to be of generic value in studying flow processes in fields of flexible vegetation.","flexible aquatic vegetation; seagrass; turbulence; drag coefficient measurements; modelling","en","journal article","American Geophysical Union","","","","","","","2011-06-01","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:e8c57b2f-74d8-402b-b3c6-e52d85344300","http://resolver.tudelft.nl/uuid:e8c57b2f-74d8-402b-b3c6-e52d85344300","On the required Reynolds-number dependence of variational multi-scale Smagorinsky models","Meyers, J.; Sagaut, P.","","2006","A theoretical analysis is presented on the dependence of the standard and variational multi-scale Smagorinsky models on the proximity of the LES filter width Delta to the integral length scale of turbulence L on the one hand, and to the Kolmogorov scale eta on the other hand. Moreover modifications of the models are formulated, which respond better to Delta/eta changes. Apart from a priori evaluations of L/Delta and Delta/eta effects, the quality of our proposed modifications to the models is further evaluated and corroborated based on LES of decaying homogeneous isotropic turbulence.","turbulence; modelling; large-eddy simulation; variational multi scale; Smagorinsky","en","conference paper","","","","","","","","","","","","","",""
"uuid:0b8c7f05-2db3-417e-8048-9795a4183986","http://resolver.tudelft.nl/uuid:0b8c7f05-2db3-417e-8048-9795a4183986","Analysis of unsteady and stratified tidal flume experiments with emphasis on turbulence, mixing and on internal gravity waves","Uittenbogaard, R.E.","","1993","","getijstromen; tidal currents; experimenteel onderzoek; experimental research; modelonderzoek; modelling; turbulentie; turbulence; menging; mixing; interne golven; internal waves; goten; flumes","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:18e869f3-cbd9-462e-a64c-be7c16a17e25","http://resolver.tudelft.nl/uuid:18e869f3-cbd9-462e-a64c-be7c16a17e25","Development of a Two-Scale Turbulence Model and Its Applications","Chen, C.J.; Singh, K.","TU Delft","1985","The use of second order closure turbulence model in predicting turbulent flows is known to be more successful than the classical mixing length model. However, it is found that if the turbulence constants are not altered or modified, the second order closure turbulence model is unable to predict satisfactorily f or some flows such as round jet and wake flows. In order to improve the predictability of the second order closure model, the present work proposes to consider two turbulent scales in the modelling of turbulent flows. One of these scales is based on using the turbulent kinetic energy, k, and its dissipation rate, epsilon, to characterize the large energy containing eddies. The other scale is based on the dissipation rate and the kinematic viscosity, nie, to characterize the small energy dissipating eddies. The second scale is based on the well known Kolmogorov hypothesis that dissipation of turbulent kinetic energy occurs primarily at small eddies. The turbulence model derived based on the concept of two different scales is called the two-scale turbulence model. The existing turbulence model which is modelled based on the one-scale concept of k and epsilon is called the one-scale turbulence model. The two-scale turbulence model is then applied to predict turbulent free shear flows and recirculating flows. The calculations were done in three parts. The first test case was nonbuoyant free shear flows which included round and plane jets in stagnant and moving streams, plane wakes and mixing layer. In the second part, the model was tested for plane and round buoyant jets having different Froude numbers. Finally, some results were obtained for recirculating flows, namely, backward facing step and flow past an obstruction. It is shown in the present study that the two-scale turbulence model performs significantly better than the one-scale turbulence model in all the cases concerned. The prediction capability of the two-scale turbulence model is shown since one does not need to alter or modify the turbulence constants as in the case of the one-scale turbulence model.","turbulence; turbulence model; two-scale model; one-scale model; turbulent flows; modelling; jet and wake flows; computational fluid dynamics","en","report","University of Iowa","","","","","","","","","","","","",""