Untitled

import numpy as np
from math import radians, sqrt, isnan

def GetU(U_inf, R, y_far, theta):
    # Placeholder function for GetU, you'll need to define its functionality
    # based on your specific use case.
    # This function should return u_t and potentially other values as needed.
    u_t = U_inf # This is a placeholder, adjust according to your actual GetU function
    return u_t, None

def Estimate_BL_D_PFT(U_inf, D, upsilon, theta_end, d_theta, dy):
    """
    Determining delta(x) boundary layer thickness and U(x) velocity at the boundary layer
    for all x from potential flow theory.
    
    Parameters:
    U_inf: Far field velocity
    D: Diameter of cylindrical body
    upsilon: Kinematic viscosity
    theta_end: Calculate the boundary layer from 0 to theta_end in degrees
    d_theta: Change in theta angle in degrees
    dy: Change in y distance from the wall
    
    Returns:
    U_x(theta): Velocity at the boundary layer for angle theta
    delta_x(theta): Thickness of boundary layer for angle theta
    """
    R = D / 2
    x_num = int(np.ceil(theta_end / d_theta))
    U_x = np.zeros(x_num)
    delta_x = np.zeros(x_num)
    
    for i in range(x_num):
        x_curr = radians(i * d_theta) * R
        if x_curr == 0:
            delta_x_curr = 0
        else:
            delta_x_curr = x_curr * 5.64 * sqrt(upsilon / U_inf / x_curr)
        
        # Fix division by zero errors
        if isnan(delta_x_curr):
            delta_x_curr = 0
        
        y_far = delta_x_curr + dy
        u_t, _ = GetU(U_inf, R, y_far, i * d_theta)
        U_x[i] = u_t
        delta_x[i] = delta_x_curr
    
    return U_x, delta_x

# Example usage:
U_inf = 10  # Example far field velocity
D = 2  # Diameter of the cylindrical body
upsilon = 1.5e-5  # Kinematic viscosity
theta_end = 180  # Calculate from 0 to 180 degrees
d_theta = 5  # Change in theta angle in degrees
dy = 0.1  # Change in y distance from the wall

U_x, delta_x = Estimate_BL_D_PFT(U_inf, D, upsilon, theta_end, d_theta, dy)
print("U_x:", U_x)
print("delta_x:", delta_x)