# Formula Symbols - D

Written by Jerry Ratzlaff on . Posted in Nomenclature & Symbols for Engineering, Mathematics, and Science

SymbolGreek SymbolDefinitionUSMetric
$$C_f$$ or $$f_D$$ - Darcy friction factor dimensionless number dimensionless number
$$Da$$ - Darcy's law - -
$$Da$$ - Darcy number dimensionless number dimensionless number
$$DW$$ - Darcy-Weisbach equation dimensionless number dimensionless number
$$De$$ - Deborah number dimensionless number dimensionless number
$$d$$ - deflection - -
$$\mu$$ mu degree of saturation - -
$$\rho$$ rho density $$lbm/ft^3$$ $$kg/m^3$$
$$z$$ - depth $$ft$$ $$m$$
$$d$$ - diameter $$ft$$ $$m$$
$$\phi$$ phi diameter $$ft$$ $$m$$
$$\Delta$$ delta differential - -
$$D$$ - diffusion coefficient - -
$$\alpha$$ alpha diffusivity $$ft^2/hr$$ $$m^2/s$$
$$a$$ - dimension $$in$$ $$m$$
$$b$$ - dimension $$in$$ $$m$$
$$K$$ - dimensionless factor - -
$$d$$ - displacement $$ft$$ $$m$$
$$\delta$$ delta displacement $$ft$$ $$m$$
$$l$$ - distance $$ft$$ $$m$$
$$d$$ - distance $$ft$$ $$m$$
$$s$$ - distance along cable $$ft$$ $$m$$
$$a$$ - distance to lowest cable point $$ft$$ $$m$$
$$C_D$$ - drag coefficient dimensionless number dimensionless number
$$F_D$$ - drag force - -
$$Du$$ - Dukhin number dimensionless number dimensionless number
$$q$$ - dynamic pressure - -
$$Q$$ - dynamic pressure - -
$$\mu$$ mu dynamic viscosity $$lbf-sec/ft^2$$ $$Pa\cdot s$$