hydcoeff

This project, titled hydcoef, is a C-based program with several functions for hydrodynamic calculations. The Makefile automates the compilation of C files and provides commands to manage the build process. The computations are based on 2D added mass coefficients estimated from theoretical calculations, with values read from the graph included in [1]. Using slender body theory, these 2D coefficients are then integrated over the ship's length according to the Salvesen method [1].

Table of Contents

• Installation
• Usage
• Makefile Commands
• Project Structure
• Contributing
• License
• References

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Installation

To get started, ensure you have the following prerequisites installed:

• GCC - The GNU Compiler Collection
• GNU Make - For executing the commands in the Makefile

Clone the Repository

Clone the project from GitHub to your local machine:

git clone https://github.com/pciuh/hydcoef.git
cd hydcoef

Usage

The project provides a Makefile to compile the source code into an executable. Once compiled, the program can be run from the command line.

To compile the program:

make all

This will generate an executable named calhyd. Further to calculate added mass and damping coefficients you need to create comma separated hull.csv including sectional ordinate x and section radius R. All these must be dimesionless with respect to ship length L.

Next the conf.csv file including ship length L and min/max value of wave frequency wMin, wMax are demanded. For preparation of csv files look into example hull/hull.csv and conf/conf.csv. Then run program from command line:

./calhyd hull/hull.csv conf/conf.csv

Added mass and damping coefficients are normalized by calculated ship displacement and pitch moment of inertia. Rsults are stored into the hull/ folder. Name of results file are e.g.: hull-hc.csv.

Makefile Commands

Below is a list of commands available in the Makefile:

Command	Description
make all	Compiles the project, producing the calhyd executable.
make calhyd	Specifically compiles and links all object files to create the calhyd executable.
make clean	Removes all object files (*.o) to clean the build environment.

Compilation Details

• Compiler: gcc
• Flags: -g3 -Wall -ggdb - These flags enable debug symbols, all warnings, and gdb debugging.
• Source Files:
  • main.c
  • adm_approx.c
  • dam_approx.c
  • hydro.c
  • in_out_files.c
  • print_coef.c
• Header File:
  • func.h

The object files generated during compilation are:

• main.o
• adm_approx.o
• dam_approx.o
• hydro.o
• in_out_files.o
• print_coef.o

In case of troubles with compilation it is recomemended to use Dockerfile then build and run image by command:

docker build -t calhyd-gcc-app .
docker run -it --rm --name calhyd-running calhyd-gcc-app

Above commands should be executed in folder hydcoef.

Project Structure

calhyd/
├── hull              # Directory containing hull files and results
├── main.c            # Main source file
├── adm_approx.c      # Source file for added mass calculations
├── dam_approx.c      # Source file for damping calculations
├── hydro.c           # Source file for hydrostatic calculations
├── in_out_file.c     # Source file for input/output flies operations
├── print_coef.c      # Source file for printing some results to screen
└── func.h            # Header file containing function declarations

Contributing

Contributions are welcome! Please follow these steps:

1. Fork the repository.
2. Create a new branch for your feature.
3. Submit a pull request.

License

This project is licensed under the MIT License. See the LICENSE file for more details.

References

[1] Faltinsen, O.M. (1990) Sea Loads on Ships and Offshore Structures. Cambridge University Press, 1-5.

@book{faltinsen1993sea,
  title={Sea Loads on Ships and Offshore Structures},
  author={Faltinsen, O.},
  isbn={9780521458702},
  lccn={90043346},
  series={Cambridge Ocean Technology Series},
  url={https://books.google.pl/books?id=qZq4Rs2DZXoC},
  year={1993},
  publisher={Cambridge University Press}
}