cm_course_tmp

This is a temporary repository for providing installation instructions of notebooks for the Coastal Modelling course.

Download and Initial Setup Instructions

1. Download the course materials from the provided link: Download Course Materials.
2. Extract the downloaded package to a location of your choice, for example, C:\Users\your_name\cm_course.

Next, navigate to the ...\cm_course\notebooks directory, open the config.py file, and update the paths for the configuration files (*.mdu & *.mdw) and the D-Hydro installation (*.dll).

Installation Instructions

We recommend using Anaconda to manage your Python installation and pip for installing additional libraries. Follow these steps after installing Anaconda:

1. Open Anaconda Prompt.
2. To create a new environment, locate the environment.yml file included in the downloaded package and run:

> conda env create -f environment.yml

3. Activate the newly created environment and launch Jupyter Notebook:

> conda activate cm_course_env
> jupyter notebook

Within the Jupyter environment, search and open the Jupyter Notebook (...\cm_course\notebooks\excercise.ipynb).

4. In the Jupyter environment, navigate to and open the exercise.ipynb notebook located in ...\cm_course\notebooks.

Using this Notebook

Once opened, click the "Run all Cells" button (⏩) to execute all cells. The raw code will be hidden by default.

Model Setup

The model consists of a 2D D-Flow and D-Waves domain. The left-hand side of the domain is onshore, the right-hand side is offshore, and the upper and bottom sides are the lateral boundaries. The boundary conditions, i.e. the water levels and wave conditions, are enforced on the offshore boundary, causing them to travel from right to left. The domain features a base resolution of approximately 20x20m, which becomes coarser towards the lateral and offshore boundaries. A schematized bathymetry is used based on a Bruun profile, combined with a 1D Gaussian shaped feature to simulate the presence of a breaker bar.

Running the Model

This Notebook enables you to run and interact with a D-Hydro (D-Flow and D-Waves) model through the Basic Modelling Interface (BMI; BMI Documentation). After initializing the model (⏩), click the "Run model" button to start the simulation. The default number of timesteps is set to 15, which are not the D-Flow timesteps (6 seconds) but are the intervals after which the models exchange information with each other and with the notebook. This exchange interval is set at 300 seconds, but can be modified in the config.py file. A certain spin-up time is necessary for the water levels and currents to stabilize after initialization. The default setting of 15 timesteps with 300-second exchange intervals (equivalent to 4500 seconds) is generally adequate for this spin-up. You are encouraged to verify this by analyzing the intermediate model results.

Plotting

The main focus of this exercise is on the center transect in the domain. The 1D plots provide a cross-shore representation of the bed level, water level, wave height, cross-shore current velocity, and resulting sediment transport rates. These plots are intended to help you understand the interaction between the coastal profile and the breaking of oblique incoming waves, as well as the resulting longshore transport. Additionally, the 2D maps offer a visual inspection tool for assessing the influence of the boundaries and the overall model stability. The slider next to the "Run model" button allows you to examine the model outcomes at different moments in time. The plot limits, whether for the y-axis or colorbar, can be dynamically adjusted using the sliders provided under Plot limits.

Changing Model Parameters

The notebook distinguishes between two types of parameters: BMI-adjustable (under Model settings) and not BMI-adjustable (Configuration settings):

1. Parameters in the Model settings category can be modified while the Notebook is active. For example, after initializing and running the model (including the initial spin-up time), you can add a breaker bar by changing hbar to 2 meters. If you press "Run model" afterward, the model will continue the simulation for the set number of timesteps, now including the modified bed level. In this case, the initial spin-up time of 15 timesteps is not required (3-5 should suffice).

2. Parameters in the Configuration settings category require restarting the model after changes. If, for instance, the value for wave height is adjusted in its respective cell, this change is saved to the configuration file. The model must be restarted to apply these changes, which is most easily done by rerunning the entire notebook (⏩). The model's initialization will then proceed based on the updated configuration file(s), either *.mdu (D-Flow) or *.mdw (D-Waves).