Johannes Lawen - Academia.edu (original) (raw)

Papers by Johannes Lawen

arXiv (Cornell University), Apr 16, 2024

To integrate wave and sediment transport modeling, a computationally extensive wave-resolving Vor... more To integrate wave and sediment transport modeling, a computationally extensive wave-resolving Voronoi mesh-based simulation has been developed to improve upon heretofore separate sediment and spectral wave modeling. Orbital wave motion-dependent sediment transport and fine structures of the dynamic Rouse number distribution across the seabed were brought into focus. The entirely parallelized waveresolving hydrodynamic model is demonstrated for nearshore beach waters adjacent to artificial islands in Doha Bay. The nested model was validated with tidal time series for three locations and two seasons.

Water, Mar 4, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

This paper presents a computational model for simulating the propagation of de mutations and pate... more This paper presents a computational model for simulating the propagation of de mutations and paternal age effects in populations. The model uses data novo for paternal mutation rates depending on age and demographic data de novo such as age distributions, birth distributions versus age, varying life expectancy, and correlations with fertility. The number of paternal de novo mutations in children increases with the paternal age at conception. This might be of interest considering that the average paternal age has risen significantly in many societies throughout the last century. The model introduced below can superimpose and extrapolate different effects based on demographic dynamics. This includes the assessment of statistically associated neurological disorders in offspring, particularly IQ decay depending on the paternal age and other medical phenotypes which constitute paternal age effects. Yearly paternal mutation rates and correlations with paternal age were used to simulate bo...

The method exploits the contraction of space to systematically obtain compact solitary solutions.... more The method exploits the contraction of space to systematically obtain compact solitary solutions. The latter are provided for the incompressible Euler and Navier-Stokes PDE. The nonlinear response of momentum advection is moved into a term for contracting space. Then the linear continuity PDE is solved by means of arbitrarily selected closure functions. The contracting space is then split into two variables. The compactness of some solutions is enhanced by numerically integrating the contracting domain while retaining a solution for the nonlinear PDE. The validation of numerical schemes is demonstrated for the Euler and Navier-Stokes PDE. As the nonlinear response is isolated in only one spatial dimension, the method permits to validate arbitrary unstructured meshes and domain geometries by introducing the spatial dimension n + 1. © 2021 Johannes Lawen

F1000Research, 2018

This paper presents a computational model for simulating the propagation of de novo mutations and... more This paper presents a computational model for simulating the propagation of de novo mutations and paternal age effects in populations. The model uses data for paternal de novo mutation rates depending on age and demographic data such as age distributions, birth distributions versus age, varying life expectancy, and correlations with fertility. The number of paternal de novo mutations in children increases with the paternal age at conception. This might be of interest considering that the average paternal age has risen significantly in many societies throughout the last century. The model introduced below can superimpose and extrapolate different effects based on demographic dynamics. This includes the assessment of statistically associated neurological disorders in offspring, particularly IQ decay depending on the paternal age and other medical phenotypes which constitute paternal age effects. Yearly paternal mutation rates and correlations with paternal age were used to simulate bo...

Continental Shelf Research, 2017

Previous research on tides and tidal dynamics in the Taiwan Strait (TS) is reviewed in this paper... more Previous research on tides and tidal dynamics in the Taiwan Strait (TS) is reviewed in this paper. Tidal dynamics, which is the basic and dominant hydrodynamics in this area, attracts much interest in the last 30 years and till now its physical mechanism is still in debate. In this study, the major research methods and findings of previous works on barotropic tides in the TS are summarized. Based on Finite Volume Coastal Ocean Model (FVCOM), the main tidal constituents (M 2 , S 2 , K 1 , O 1) are well simulated with the mean root-mean-square (RMS) errors of 4.7, 2.0, 1.3 and 0.7cm between the observed and simulated tidal constants, respectively. It has been proved that semi-diurnal tidal movement is mainly determined by the waves from the East China Sea (ECS), while waves from the ECS and the Luzon Strait (LS) play comparable roles in diurnal tidal movement in the TS by linear superposition and the interaction of these two waves is the main cause for the progressive diurnal tidal waves in the TS. Furthermore, energy analysis revealed that the M 2 tidal wave system in the TS and its adjacent area south to the shoal is an standing wave system and the anti-node appears in the central TS while the wave node locates in the shoal area, which can be contributed to the interaction of the incident waves from the ECS and the topography step south to Taiwan island, while the shoal also has an impact on the whole semi-diurnal tidal wave system in the TS. This standing wave system is consistent with the little energy dissipation in the central TS and much energy dissipation in the southern TS, where the shallow water effect also contributes to the local dissipation to some extent.

Proceedings of the 2nd Annual Gas Processing Symposium, 2010

... Processing Symposium Farid Benyahia and Fadwa T. Eljack (Editors) ?? 2010 Elsevier BV All rig... more ... Processing Symposium Farid Benyahia and Fadwa T. Eljack (Editors) ?? 2010 Elsevier BV All rights reserved. 99 Industrial Water Discharge and Biocide Fate Simulations with Nonlinear Conversion Johannes Lawen, ac Yu Huaming, b Patrick Linke, a Ahmed Abdel-Wahaba ...

Environmental Modeling & Assessment, 2013

ABSTRACT A new unstructured mesh coastal water and air quality model has been developed that incl... more ABSTRACT A new unstructured mesh coastal water and air quality model has been developed that includes species transport, nonlinear decay, byproduct formation and mass-exchange between sea and atmosphere. The model has been programmed with a graphical interface and is applicable to coastal seawater, lakes and rivers. Focused on species conversion and interaction with the atmosphere, the water and air quality model follows a modular approach. It is a compatible module which simulates distributions based on fluid dynamic field data of underlying existing hydrodynamic and atmospheric simulations. Nonlinear and spline approximations of decay and growth kinetics, byproduct formation and joint sea–atmosphere simulation have been embedded. The Windows application software includes functions allowing error analysis concerning mesh and finite volume approximation. In this work, an anoxic submerged process-water discharge has been simulated. An error analysis has been carried out by varying vertical meshing, time-steps and comparing results based on explicit and implicit finite volume approximation.