Python utilities for zCFD users

zutil is a comprehensive Python toolkit designed to work with zCFD CFD simulation results and provide powerful pre- and post-processing capabilities. This library offers streamlined workflows for data analysis, visualization, wind energy modeling, acoustic analysis, and geometric transformations.

Install zutil from PyPI:

pip install zutil

Note: This library is compatible with Paraview 6.0+

zutil is organized into several specialized modules:

• plot - Advanced plotting and visualization tools for zCFD results
• post - Post-processing utilities using Paraview integration
• fileutils - File I/O operations and result data access
• analysis - Analysis tools including acoustic analysis
• transform - Geometric transformation utilities
• zWind - Wind energy modeling and turbine analysis

The fundamental function for accessing zCFD simulation data:

from zutil.fileutils import get_zcfd_result

# Load a zCFD case result
result = get_zcfd_result('my_case.py')

# Access case parameters
params = result.parameters

# Get report data
report = result.report
print(report.header_list)  # Available data columns

Create professional plots from zCFD report files:

from zutil.plot import Report
import matplotlib.pyplot as plt

# Load and plot residuals
report = Report('my_case.py')
report.plot_residuals()
plt.show()

# Plot specific variables
report.plot_report_array('Cd')
plt.show()

The zutil.plot module provides comprehensive plotting capabilities:

from zutil.plot import Report, zCFD_Plots

# Individual case plotting
report = Report('case.py')
report.plot_residuals()
report.plot_forces()
report.plot_linear_solve_performance()

# Multi-case plotting (handles overset cases automatically)
plots = zCFD_Plots('case.py')
plots.plot_residuals()
plots.plot_forces()

Key Features:

• Residual convergence plots
• Force and moment coefficient plotting
• Linear solver performance analysis
• Acoustic analysis visualization
• Professional styling with zCFD branding

The zutil.post module integrates with Paraview for advanced post-processing:

Note: This module requires pvpython to be installed. The easiest way to get this is to use a distribution of zCFD.

from zutil import post

# Access case parameters
params = post.get_case_parameters('case.py')

# Calculate forces on walls
force = post.calc_force_wall('wall_name', 'case.py')

# Extract surface pressure profiles
cp_data = post.cp_profile_wall_from_file('wall_name', 'case.py')

# Generate Paraview visualizations with zCFD branding
post.vtk_logo_stamp()

Key Features:

• Force and moment calculations
• Surface pressure and friction analysis
• Paraview visualization utilities
• Progress tracking for batch operations

The zutil.fileutils module handles all file I/O operations:

from zutil.fileutils import get_zcfd_result, zCFD_Result

# Load case data
result = get_zcfd_result('case.py')

# Access report data directly
report_data = result.report.get_array('Cd')

# Get case status
success = result.report.get_case_success()

Key Features:

• Seamless access to zCFD case data
• Report file parsing and analysis
• Parameter extraction from control files
• CSV data handling utilities

The zutil.analysis module includes acoustic and other analysis capabilities:

from zutil.analysis.acoustic import calculate_PSD
from zutil.plot import plot_PSD, plot_thirdoctave

# Perform acoustic analysis
psd_data = calculate_PSD(time_series_data, sample_rate)

# Create acoustic plots
plot_PSD(psd_data, frequencies)
plot_thirdoctave(psd_data, frequencies)

Key Features:

• Power spectral density (PSD) analysis
• Third-octave band analysis
• Acoustic visualization tools
• Signal processing utilities

The zutil.transform module provides coordinate and geometric operations:

from zutil.transform import transform
from zutil import vector_from_angle, rotate_vector

# Coordinate transformations
transformed_points = transform.apply_rotation(points, rotation_matrix)

# Vector operations
wind_vector = vector_from_angle(wind_direction, wind_speed)
rotated_vector = rotate_vector(vector, axis, angle)

Key Features:

• Coordinate system transformations
• Vector mathematics utilities
• Rotation and translation operations
• Unit conversions

The zutil.zWind module provides specialized wind energy tools:

from zutil.zWind import zTurbine

# Define wind turbine properties
turbine = zTurbine(name='NREL_5MW', centre=[0, 0, 90])

Key Features:

• Wind turbine modeling (zTurbine)
• Actuator disc implementations (zActuatorDisc)
• Blade element momentum theory (zBem)
• Turbine controllers (zController)

• Python 3.9+
• NumPy
• Pandas
• Matplotlib
• IPython/Jupyter support
• PyYAML
• Paraview (for post-processing features)

For comprehensive documentation, tutorials, and examples:

• Full Documentation: https://docs.zenotech.com/
• zCFD Solver: Download a free trial at https://zcfd.zenotech.com

• Issues: Report bugs and feature requests via the Issues tab
• Email: For technical support contact [email protected]

zutil is released under the MIT License. See LICENSE file for details.

Developed by Zenotech Ltd