# Formula Symbols - S

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

SymbolGreek SymbolDefinitionUSMetric
$$S$$ - sag $$ft$$ $$m$$
$$e_s$$ - saturated vapor pressure - -
$$Sc$$ - Schmidt number dimensionless number dimensionless number
$$v_s$$ - seepage velocity - -
$$H$$ - shape factor dimensionless number dimensionless number
$$G$$ - shear modulus $$lbf/in^2$$ $$Pa$$
$$\gamma$$ gamma shear strain $$rad$$ $$rad$$
$$\tau$$ tau shear stress $$lbf/ft^2$$ $$Pa$$
$$Sh$$ - Sherwood number dimensionless number dimensionless number
$$\mu$$ mu simple viscosity $$lbf-sec/ft^2$$ $$Pa\cdot s$$
$$G$$ - slipping - -
$$m$$ - slope $$ft$$ $$m$$
$$S$$ - Sommerfield number dimensionless number dimensionless number
$$a$$ - sound $$ft/sec$$ $$m/s$$
$$h$$ - specific enthalpy $$Btu/lbm$$ $$kJ/kg$$
$$R$$ - specific gas constant $$ft-lbf/lbm-^\circ R$$ $$kJ/kg \cdot K$$
$$SG$$ - specific gravity dimensionless number dimensionless number
$$c$$ - specific heat $$Btu/lbm-^\circ F$$ $$kJ/kg \cdot ^\circ C$$
$$Q$$ - specific heat capacity $$Btu/lbm-^\circ F$$ $$kJ/kg \cdot ^\circ C$$
$$C_p$$ - specific heat constant pressure - -
$$C_v$$ - specific heat constant volume - -
$$I_{sp}$$ - specific impulse $$sec$$ $$s$$
$$u$$ - specific internal energy $$Btu/lbm$$ $$kJ/kg$$
$$\upsilon$$ upsilon specific volume $$ft^3/lbm$$ $$m^3/kg$$
$$\gamma$$ gamma specific weight $$lbf/ft^3$$ -
$$n$$ - speed $$ft/sec$$ $$m/s$$
$$v$$ - speed $$ft/sec$$ $$m/s$$
$$a$$ - speed of sound $$ft/sec$$ $$m/s$$
$$k_s$$ - spring constant $$lbf/ft$$ $$N/m$$
$$d_s$$ - spring displacement - -
$$F_s$$ - spring force - -
$$St$$ - Stanton number dimensionless number dimensionless number
$$SE$$ - static efficiency - -
$$f_s$$ - static friction - -
$$\mu_s$$ mu static friction coefficient dimensionless number dimensionless number
$$SP$$ - static pressure $$in\;wg$$ $$Pa$$
$$\Psi$$ Psi steam function - -
$$\Phi$$ Phi steam potential - -
$$Ste$$ - Stefan number dimensionless number dimensionless number
$$\sigma$$ sigma Stefan-Boltzmann constant - -
$$St$$ - Stokes' Law - -
$$\epsilon$$ epsilon strain $$in/in$$ $$m/mdeg$$
$$\sigma$$ sigma stress $$in/in$$ $$m/mdeg$$
$$S$$ sigma stress $$in/in$$ $$m/mdeg$$
$$L$$ - stroke $$ft$$ $$m$$
$$L$$ - stroke length $$ft$$ $$m$$
$$S$$ - strength $$lbf/in^2$$ $$Pa$$
$$Sr$$ - Strouhal number dimensionless number dimensionless number
$$N$$ - Stuart number dimensionless number dimensionless number
$$\sigma$$ sigma surface tension $$lbf/ft$$ $$N/m$$