app.py

import streamlit as st
import pandas as pd
import numpy as np

st.write("""
         ## First Layer Thickness Calculation based on y+
         """)
         
with st.form("my_form"):
    # Fluid properties
    mu =  st.number_input("Viscosity [Pa*s]", step=1e-6, format="%.7f")
    rho = st.number_input("Density [kg/m^3]", step=1e-6, format="%.5f")
    st.form_submit_button('Submit properties')


nu = mu/rho     # Dynamic viscosity [m^2/s]
    

# Flow properties
D = st.number_input("Characteristic Length [m]", step=1e-6, format="%.5f")         # Characteristic Length [m]
u_inf = st.number_input("Freestream velocity [m/s]", step=1e-6, format="%.5f")    # Freestream velocity [m/s]
y_plus = st.number_input("Y+ [-]", step=1e-6, format="%.5f")    # Y+ [-]

Re = rho*u_inf*D/mu     # Reynold's number
C_f = .0576*Re**(-.2)   # Skin friction coefficient

st.write("""
         ## f'Reynolds = {Re:.0f}'
         """)

tau_om = .5*C_f*rho*u_inf**2

u_tau = (tau_om/rho)**.5

y = y_plus*nu/u_tau

print(f'Y Centroid = {y:.4f}')
print(f'Yh (First Layer Thickness) = {2*y:.4f}')