Sail with camber#
In the cell below insert your initial parameters. If some of them are not required for your model, simply pass 0 value (for numbers). Some parameters are necessary only for specific cases like roughness (used by package when logarithmic profile is set) and they are omitted during computation.
ATTENTION:
Make sure that the length of your arrays match, like: girths and chords
More information can be found in code comments below.
# varaibles.py for jupyter
import os
import numpy as np
import time
from pySailingVLM.runner.container import Output, Rig, Conditions, Solver, MainSail, JibSail, Csys, Keel
mgirths = np.array([0.00, 1./8, 1./4, 1./2, 3./4, 7./8, 1.00])
jgirths = np.array([0.00, 1./4, 1./2, 3./4, 1.00])
out = Output(case_name='my_case_name',
case_dir=os.path.abspath(''),
name=os.path.join("results_example_jib_and_mainsail_vlm", time.strftime("%Y-%m-%d_%Hh%Mm%Ss")),
file_name='my_file_name')
solver = Solver(n_spanwise=15,
n_chordwise=4,
interpolation_type='spline')
conditions = Conditions(leeway_deg=5.,
heel_deg=10.,
SOG_yacht=4.63,
tws_ref= 4.63,
alpha_true_wind_deg= 50.,
reference_water_level_for_wind_profile=-0.,
wind_exp_coeff=0.1428,
wind_reference_measurment_height=10.,
rho=1.225,
wind_profile='exponential',
roughness=0.05)
rig = Rig(main_sail_luff=12.4,
jib_luff=10.0,
foretriangle_height=11.50,
foretriangle_base=3.90,
sheer_above_waterline=1.2,
boom_above_sheer=1.3,
rake_deg=92.,
mast_LOA=0.15,
sails_def='jib_and_main')
main = MainSail(centerline_twist_deg=None,
girths=np.array([0.00, 1./8, 1./4, 1./2, 3./4, 7./8, 1.00]),
chords=np.array([4.00, 3.82, 3.64, 3.20, 2.64, 2.32, 2.00]),
camber=5*np.array([0.01, 0.01, 0.01, 0.01, 0.01, 0.01, 0.01]),
camber_distance_from_luff=np.array([0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5]))
jib = JibSail(centerline_twist_deg=None,
girths=np.array([0.00, 1./4, 1./2, 3./4, 1.00]),
chords=np.array([3.80, 2.98, 2.15, 1.33, 0.5]),
camber=0*np.array([0.01, 0.01, 0.01, 0.01, 0.01]),
camber_distance_from_luff=np.array([0.5, 0.5, 0.5, 0.5, 0.5]))
csys = Csys(reference_level_for_moments=np.array([0, 0, 0]))
keel = Keel(center_of_lateral_resistance_upright=np.array([0, 0, -1.0]))
Run cell below twice: Run cell below twice before running other cells. Output below is expected to always appear at first time importing pySailingVLM:
/home/user/miniconda3/envs/mgr_test/lib/python3.10/site-packages/numba/core/lowering.py:107: NumbaDebugInfoWarning: Could not find source for function:. Debug line information may be inaccurate.warnings.warn(NumbaDebugInfoWarning(msg))
/home/user/miniconda3/envs/mgr_test/lib/python3.10/site-packages/numba/core/lowering.py:107: NumbaDebugInfoWarning: Could not find source for function:
import shutil
from pySailingVLM.rotations.csys_transformations import CSYS_transformations
from pySailingVLM.yacht_geometry.hull_geometry import HullGeometry
from pySailingVLM.results.save_utils import save_results_to_file
from pySailingVLM.solver.panels_plotter import display_panels_xyz_and_winds
from pySailingVLM.results.inviscid_flow import InviscidFlowResults
from pySailingVLM.solver.vlm import Vlm
from pySailingVLM.runner.sail import Wind, Sail
from pySailingVLM.solver.panels_plotter import plot_cp
csys_transformations = CSYS_transformations(
conditions.heel_deg, conditions.leeway_deg,
v_from_original_xyz_2_reference_csys_xyz=csys.reference_level_for_moments)
w = Wind(conditions)
s = Sail(solver, rig, main, jib, csys_transformations)
sail_set = s.sail_set
hull = HullGeometry(rig.sheer_above_waterline, rig.foretriangle_base, csys_transformations, keel.center_of_lateral_resistance_upright)
myvlm = Vlm(sail_set.panels, solver.n_chordwise, solver.n_spanwise, conditions.rho, w.profile, sail_set.trailing_edge_info, sail_set.leading_edge_info)
inviscid_flow_results = InviscidFlowResults(sail_set, csys_transformations, myvlm)
inviscid_flow_results.estimate_heeling_moment_from_keel(hull.center_of_lateral_resistance)
Cell below displays computations and saves integrals to output file.
Tip: For proper rendering of matplotlib figures in jupyter notebooks insert %matplotlib widget before calling plot functions.
%matplotlib widget
print("Preparing visualization.")
display_panels_xyz_and_winds(myvlm, inviscid_flow_results, myvlm.inlet_conditions, hull, show_plot=True) # add show_apparent_induced_wind=True for apparent + induced wind
df_components, df_integrals, df_inlet_IC = save_results_to_file(myvlm, csys_transformations, inviscid_flow_results, s.sail_set, out.name, out.file_name)
import matplotlib. pyplot as plt
plt.savefig('sailing_fig')
Preparing visualization.
Lets see our integrals :)
print(f"-------------------------------------------------------------")
print(f"Notice:\n"
f"\tThe forces [N] and moments [Nm] are without profile drag.\n"
f"\tThe the _COG_ CSYS is aligned in the direction of the yacht movement (course over ground).\n"
f"\tThe the _COW_ CSYS is aligned along the centerline of the yacht (course over water).\n"
f"\tNumber of panels (sail s.sail_set with mirror): {s.sail_set.panels.shape}")
df_integrals
-------------------------------------------------------------
Notice:
The forces [N] and moments [Nm] are without profile drag.
The the _COG_ CSYS is aligned in the direction of the yacht movement (course over ground).
The the _COW_ CSYS is aligned along the centerline of the yacht (course over water).
Number of panels (sail s.sail_set with mirror): (240, 4, 3)
| Quantity | Value | |
|---|---|---|
| 0 | F_jib_total_COG.x | -194.910017 |
| 1 | F_jib_total_COG.y | 446.957244 |
| 2 | F_jib_total_COG.z | -32.279372 |
| 3 | F_main_sail_total_COG.x | -390.594481 |
| 4 | F_main_sail_total_COG.y | 1113.411846 |
| 5 | F_main_sail_total_COG.z | -213.001146 |
| 6 | F_sails_total_COG.x | -585.504498 |
| 7 | F_sails_total_COG.y | 1560.369090 |
| 8 | F_sails_total_COG.z | -245.280518 |
| 9 | F_sails_total_COW.x | -719.271604 |
| 10 | F_sails_total_COW.y | 1503.401335 |
| 11 | F_sails_total_COW.z | -245.280518 |
| 12 | M_jib_total_COG.x | -2352.912026 |
| 13 | M_jib_total_COG.y | -1155.077251 |
| 14 | M_jib_total_COG.z | -681.331651 |
| 15 | M_keel_total_COG.x | -1579.094015 |
| 16 | M_keel_total_COG.y | -580.321551 |
| 17 | M_keel_total_COG.z | 77.669591 |
| 18 | M_keel_total_COW.x (heel) | -1522.506729 |
| 19 | M_keel_total_COW.y (pitch) | -715.740364 |
| 20 | M_keel_total_COW.z (yaw - JG sign) | -77.669591 |
| 21 | M_keel_total_COW.z (yaw) | 77.669591 |
| 22 | M_main_sail_total_COG.x | -9718.978453 |
| 23 | M_main_sail_total_COG.y | -3203.265665 |
| 24 | M_main_sail_total_COG.z | 2436.064550 |
| 25 | M_sails_total_COG.x | -12071.890479 |
| 26 | M_sails_total_COG.y | -4358.342915 |
| 27 | M_sails_total_COG.z | 1754.732899 |
| 28 | M_sails_total_COW.x (heel) | -11646.098677 |
| 29 | M_sails_total_COW.y (pitch) | -5393.892686 |
| 30 | M_sails_total_COW.z (yaw - JG sign) | -1754.732899 |
| 31 | M_sails_total_COW.z (yaw) | 1754.732899 |
| 32 | M_total_COG.x | -13650.984493 |
| 33 | M_total_COG.y | -4938.664467 |
| 34 | M_total_COG.z | 1832.402491 |
| 35 | M_total_COW.x (heel) | -13168.605406 |
| 36 | M_total_COW.y (pitch) | -6109.633050 |
| 37 | M_total_COW.z (yaw - JG sign) | -1832.402491 |
| 38 | M_total_COW.z (yaw) | 1832.402491 |
Compute aerodynamic parameters:
Make model plot in 2D colored by pressure coefficients:
from pySailingVLM.solver.panels_plotter import plot_cp
plot_cp(sail_set.zero_mesh, myvlm.p_coeffs, out.name)
Calculate section coefficient per each sail, plot results and save to file.
from pySailingVLM.solver.panels_plotter import plot_cp, plot_section_coeff
from pySailingVLM.solver.coefs import get_data_for_coeff_plot
mean_cp, cl_data, cd_data = get_data_for_coeff_plot(myvlm, solver)
plot_section_coeff(cd_data, mean_cp, out.name, 'lift', ['blue', 'green'])
plot_section_coeff(cl_data, mean_cp, out.name, 'drag', ['teal', 'purple'])
Thats all. Experiment and play with this code on your own.