Package: openplaning
OpenPlaningOpenPlaning is a Python library for the hydrodynamic evaluation of planing hulls based on the Savitsky empirical methods.InstallationUse the package managerpipto install openplaning.pipinstallopenplaningExamplesYou can run the example below, plus an optimization case study, online with Binder:fromopenplaningimportPlaningBoat#Vessel particulars (from the Savitsky '76 example)speed=13.07#m/sweight=827400#Nbeam=7.315#mlength=24.38#m, vessel LOAlcg=10.67#m, long. center of gravityvcg=beam/7#m, vert. center of gravityr_g=0.25*length#m, radius of gyrationbeta=15#deg, deadrise#Propulsionepsilon=0#deg, thrust angle w.r.t. keelvT=vcg#m, thrust vertical distancelT=lcg#m, thrust horizontal distance#Trim tab particularssigma=1.0#flap span-hull beam ratiodelta=5#deg, flap deflectionLf=0.3048#m, flap chord#SeawayH_sig=1.402#m, significant wave height#Create boat objectboat=PlaningBoat(speed,weight,beam,lcg,vcg,r_g,beta,epsilon,vT,lT,length,H_sig,Lf=Lf,sigma=sigma,delta=delta,wetted_lengths_type=3)#Calculates the equilibrium trim and heave, and updates boat.tau and boat.z_wlboat.get_steady_trim()boat.print_description()# RETURNS:# ---VESSEL---# Speed            13.07 m/s# V_k              25.40808 knot# Fn (beam)        1.543154# Fn (volume)      2.001392## Weight           827400 N# Mass             84371.75 kg# Volume           82.24409 m³# Beam             7.315 m# LCG              10.67 m from stern# VCG              1.045 m from keel# R_g              6.095 m# Deadrise         15 deg## LOA              24.38 m# AHR              0.00015 m, average hull roughness## ---ATTITUDE---# z_wl             0.1384811 m, vertical distance of center of gravity to the calm water line# tau              2.878945 deg, trim angle# η₃               0 deg, additional heave#η₅               0 deg, additional trim#Transom draft    1.441111 m, draft of keel at transom## ---PROPULSION---# Thrust angle     0 deg w.r.t. keel (CCW with body-fixed origin at 9 o'clock)# LCT              10.67 m from stern, positive forward# VCT              1.045 m from keel, positive up## ---FLAP---# Chord            0.3048 m# Span/Beam        1# Angle            5 deg w.r.t. keel (CCW with body-fixed origin at 9 o'clock)## ---AIR DRAG---# l_air            0 m, distance from stern to center of air pressure# h_air            0 m, height from keel to top of square which bounds the air-drag-inducing shape# b_air            0 m, transverse width of square which bounds the air-drag-inducing shape# C_shape          0 area coefficient for air-drag-inducing shape. C_shape = 1 means the air drag reference area is h_air*b_air# C_D              0.7 air drag coefficient## ---ENVIRONMENT---# ρ                1025.87 kg/m³, water density# ν                1.19e-06 m²/s, water kinematic viscosity# ρ_air            1.225 kg/m³, air density# g                9.8066 m/s², gravitational acceleration## ---WETTED LENGTH OPTIONS---# LC_type          3 (1 = Use Faltinsen 2010 wave rise approximation, 2 = Use Savitsky's '64 approach, 3 = Use Savitsky's '76 approach)# zmax_type        1 (1 = Uses 3rd order polynomial fit (faster, recommended), 2 = Use cubic interpolation)## ---WETTED LENGTHS---# L_K              28.69256 m, keel wetted length# L_C              17.67617 m, chine wetted length# λ                3.199428 mean wetted-length to beam ratio (L_K+L_C)/(2*beam)# x_s              11.0164 m, distance from keel/water-line intersection to start of wetted chine# z_max            0.7704615 maximum presssure coordinate coefficient (z_max/Ut)## ---FORCES [F_x (N, +aft), F_z (N, +up), M_cg (N*m, +pitch up)]---# Hydrodynamic Force =# [39245.86 780400.3 301189.8]## Skin Friction =# [31893.98 -1603.929 -18962.39]## Air Resistance =# [0 0 0]## Flap Force =# [1840.949 44933.51 -282227.4]## Net Force =# [72980.79 2.608704e-08 2.55066e-07]## Resultant Thrust =# [-72980.79 3670.16 0]### ---THURST & POWER---# Thrust Magnitude 73073.02 N# Effective Thrust 72980.79 N# Eff. Power       953.859 kW# Eff. Horsepower  1279.146 hp## ---EOM MATRICES---# Mass matrix, [kg, kg*m/rad; kg*m, kg*m²/rad] =# [[501800.8 67648.82]#  [67648.82 2.046024e+07]]## Damping matrix, [kg/s, kg*m/(s*rad); kg*m/s, kg*m²/(s*rad)] =# [[447299.8 -8182636]#  [3078703 2.909537e+07]]## Restoring matrix, [N/m, N/rad; N, N*m/rad] =# [[1325673 -2390482]#  [4940227 5.375431e+07]]### ---PORPOISING---# [[Eigenvalue check result, Est. pitch settling time (s)],#  [Savitsky chart result, Critical trim angle (deg)]] =# [[0 7.097941]#  [0 9.955598]]### ---BEHAVIOR IN WAVES---# H_sig            1.402 m, significant wave heigth# R_AW             38406.03 N, added resistance in waves# Average impact acceleration [n_cg, n_bow] (g's) =# [0.3082269 0.754686]DependenciesNumPySciPyndmathContributingContributions and feedback are welcome and greatly appreciated. Feel free to open an issue first to discuss what you would like to change.LicenseMITCitingThis package was presented as a conference paper at the SNAME FAST Conference 2021:Castro-Feliciano, E. L., 2021, "OpenPlaning: Open-Source Framework for the Hydrodynamic Design of Planing Hulls," SNAME FAST '21 Conference ProceedingsReferencesCastro-Feliciano, E. L., Sun, J., and Troesch, A. W., 2017, "First Step Toward the Codesign of Planing Craft and Active Control Systems," J. Offshore Mech. Arct. Eng., 139(1)Faltinsen, O. M., 2005, "Planing Vessels," Hydrodynamics of High-Speed Marine Vehicles, Cambridge University Press, New York, p. 342.Fridsma, G., 1971, "A Systematic Study of the Rough-Water Performance of Planing Boats (Irregular Waves - Part II)," Tech. Rep. 1495, Stevens Institute of TechnologyHadler, J. B., 1966, "The Prediction of Power Performance on Planing Craft," SNAME Trans., 74, pp. 563–610.Savitsky, D., 1964, "Hydrodynamic Design of Planing Hulls," Mar. Technol., 1(1), pp. 71–94.Savitsky, D., and Brown, P. W., 1976, "Procedures for Hydrodynamic Evaluation of Planing Hulls in Smooth and Rough Water," Mar. Technol., 13(4), pp. 381-400