# Formula Symbols - H

on . Posted in Nomenclature & Symbols for Engineering, Mathematics, and Science

## Formula Symbols

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## H

SymbolGreek SymbolDefinitionEnglishMetricSIValue
$$Hg$$ - Hagen number dimensionless -
$$\Delta p$$ - Hagen–Poiseuille $$\large{\frac{lbf}{in^2}}$$ $$Pa$$ $$kg- m^{-1}-s^{-2}$$ -
$$T_{\frac{1}{2}}$$, $$\;\tau_{\frac{1}{2}}$$ tau half life - - -  -
$$A_h$$, $$\;R_h$$ - Hall coefficient - - -  -
$$H$$ - Hamiltonian function - - -  -
$$Ha$$  - Hartmann number dimensionless  -
$$E_h$$  - Hartree energy  $$lbf-ft$$ $$J$$ $$kg - m^2 - s^{-2}$$ $$4.359\;744\;722\;2071\;(85)\;x\;10^{-18}$$ $$J$$
$$Ha$$  - Hatta number dimensionless -
$$P_h$$  - Havnes number dimensionless -
$$C$$ - Hazen-Williams coefficient dimensionless -
$$Q$$ - Hazen-Williams flow rate $$\large{\frac{ft^3}{sec}}$$ $$\large{\frac{m^3}{s}}$$ $$m^3-s^{-1}$$ -
$$p_d$$ - Hazen-Williams flow through a pressurized pipe $$\large{\frac{lbf}{in^2}}$$ $$Pa$$ $$kg- m^{-1}-s^{-2}$$ -
$$v$$ - Hazen-Williams flow through a open channel $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$ $$m-s^{-1}$$  -
$$h_f$$ - Hazen-Williams head loss due to friction $$ft$$ $$m$$ $$m$$ -
$$m$$  - Hazen-Williams hydraulic grade $$ft$$ $$m$$ $$m$$ -
$$r_h$$  - Hazen-Williams hydraulic radius $$in$$ $$mm$$ $$mm$$  -
$$v$$  - Hazen-Williams mean flow velocity $$\large{\frac{ft}{sec}}$$ $$\large{\frac{m}{s}}$$ $$m - s^{-1}$$  -
$$d$$  - Hazen-Williams pipe inside diameter $$in$$ $$mm$$ $$mm$$  -
$$hc$$ - hc constant -
$$h$$ - head $$ft$$ $$m$$ $$m$$ -
$$h_f$$ - head friction loss in fittings and valves   dimensionless  -
$$h_f$$ - head fractional resistance - - - -
$$HGV$$ - head gasket volume $$in^3$$  $$mm^3$$  $$mm^3$$  $$HGV$$-
$$h_l$$ - head loss $$ft$$ $$m$$ $$m$$ -
$$h_f$$ - head loss due to ftiction $$ft$$ $$m$$ $$m$$ -
$$p$$ - head pressure $$\large{\frac{lbf}{in^2}}$$ $$Pa$$ $$kg-m^{-1}-s^{-2}$$ -
$$v$$ - head velocity $$\large{\frac{ft}{sec}}$$  $$\large{\frac{m}{s}}$$ $$m-s^{-1}$$ -
$$h_{dv}$$ - head velocity discharge $$ft$$ $$m$$ $$m$$ -
$$h_{sv}$$ - head velocity suction $$ft$$ $$m$$ $$m$$ -
$$Q$$ - heat $$\large{\frac{Btu}{lbm}}$$ $$\large{\frac{kJ}{kg}}$$ $$kJ-kg^{-1}$$ -
$$\partial$$  partial heat as a path function - - - -
$$C$$, $$\;c_p$$ - heat capacity $$\large{\frac{Btu}{F}}$$ $$\large{\frac{kJ}{K}}$$ $$kJ-K^{-1}$$   -
$$C_p$$ - heat capacity at constant pressure $$\large{\frac{Btu}{F}}$$ $$\large{\frac{kJ}{K}}$$ $$kJ-K^{-1}$$   -
$$C_v$$ - heat capacity at constant volume $$\large{\frac{Btu}{F}}$$ $$\large{\frac{kJ}{K}}$$ $$kJ-K^{-1}$$   -
$$\gamma$$, $$\;\kappa$$, $$\;k$$ gamma, kappa heat capacity ratio dimensionless -
$$Q_c$$ - heat conduction $$\large{\frac{Btu}{hr}}$$ $$W$$ $$kg-m^2-s^{-3}$$ -
$$\lambda$$ lambda heat conductivity - - - -
$$C_p$$ - heat constant pressure - - - -
$$C_v$$ - heat constant volume - - - -
$$q$$ - heat content $$\large{\frac{Btu}{lbm}}$$ $$\large{\frac{J}{kg}}$$ $$J-kg^{-1}$$ -
$$Q$$ - heat convection - - - -
$$\Delta Q$$ - heat differential $$\large{\frac{Btu}{lbm}}$$ $$\large{\frac{J}{kg}}$$ $$J-kg^{-1}$$  -
$$\kappa$$ kappa heat diffusivity $$\large{\frac{ft^2}{sec}}$$ $$\large{\frac{m^2}{s}}$$ $$m^2-s^{-1}$$  -
$$Q$$, $$\;q$$ - heat energy - - - -
$$Q$$, $$\;Q_f$$, $$\;\Phi$$ Phi heat flow rate $$\large{\frac{Btu}{hr}}$$ $$W$$ $$kg-m^2-s^{-3}$$ -
$$Q"$$ - heat flux $$\large{\frac{Btu}{hr-ft^2}}$$  $$\large{\frac{W}{m^2}}$$ $$W-m^{-2}$$ -
$$q$$ - heat loss $$F$$ $$C$$ $$x+273.15\;K$$ -
$$K$$ - heat loss coefficient of a device dimensionless -
$$d$$ - heat penetration $$in$$ $$mm$$ $$mm$$ -
$$Q$$, $$\;\phi$$ phi heat radiation - - - -
$$HRR$$ - heat release rate $$\large{\frac{Btu}{ft^2-hr}}$$ $$\large{\frac{W}{m^2}}$$ $$W-m^{-2}$$ -
$$Q$$ - heat transfer $$\large{\frac{Btu}{hr}}$$ $$W$$ $$kg-m^2-s^{-3}$$ -
$$Q_c$$ - heat transfer by conduction $$\large{\frac{Btu}{hr}}$$ $$W$$ $$kg-m^2-s^{-3}$$ -
$$R_t$$ - heat transfer by conduction resistance through a cylindrical wall $$\large{\frac{hr-F}{Btu}}$$ $$\large{\frac{K}{W}}$$  $$K-W^{-1}$$ -
$$Q_c$$  - heat transfer by conduction through a cylindrical wall $$\large{\frac{Btu}{hr}}$$  $$W$$ $$kg-m^2-s^{-3}$$  -
$$Q_c$$ - heat transfer by conduction through a plane wall $$\large{\frac{Btu}{hr}}$$  $$W$$ $$kg-m^2-s^{-3}$$ -
$$Q_c$$ - heat transfer by convection $$\large{\frac{Btu}{hr}}$$ $$W$$ $$kg-m^2-s^{-3}$$ -
$$Q_r$$ - heat transfer by radiation $$\large{\frac{Btu}{hr}}$$ $$W$$ $$kg-m^2-s^{-3}$$ -
$$h$$, $$\;h_c$$ - heat transfer coefficient $$\large{\frac{Btu}{hr-ft^2-F}}$$  $$\large{\frac{W}{m^2-K}}$$ $$W-m^{-2} -K^{-1}$$ -
$$h_{wall}$$ - heat transfer coefficient of a pipe wall $$\large{\frac{Btu}{hr-ft^2-F}}$$  $$\large{\frac{W}{m^2-K}}$$ $$W-m^{-2} -K^{-1}$$ -
$$Q_t$$ - heat transfer rate $$\large{\frac{Btu}{hr}}$$ $$W$$ $$kg-m^2-s^{-3}$$ -
$$Q$$ - heat transfer to a system $$\large{\frac{Btu}{hr}}$$ $$W$$ $$kg-m^2-s^{-3}$$ -
$$H_v$$ - heat of vaporization $$\large{\frac{Btu}{lbm}}$$ $$\large{\frac{J}{kg}}$$ $$J-kg^{-1}$$ -
$$HV$$ - heating value $$\large{\frac{Btu}{lbm}}$$ $$\large{\frac{kJ}{kg}}$$ $$J-kg^{-1}$$ -
$$h$$ - height $$ft$$ or $$in$$ $$m$$ or $$mm$$ $$m$$ or $$mm$$ -
$$h_1$$ - height of drivers' eyes above the roadway surface $$ft$$ $$m$$ $$m$$ -
$$h_2$$ - height of object above the roadway surface $$ft$$ $$m$$ $$m$$ -
$$He$$ - Hedstrom number dimensionless -
$$h$$ - height of fluid column $$ft$$ or $$in$$ $$m$$ or $$mm$$ $$m$$ or $$mm$$ -
$$A$$ - Helmholtz function - - - -
$$He$$ - Helmholtz number dimensionless -
$$C$$ - Henry's law $$\large{\frac{mol}{gal}}$$ $$\large{\frac{mol}{L}}$$ $$mol-L^{-1}$$ -
$$H_s$$ - Henry's law constant (solubility) - $$\large{\frac{mol}{m^3-Pa}}$$ $$mol-m^{-3}-Pa^{-1}$$ -
$$H_v$$ - Henry's law constant (volatility) - $$\large{\frac{m^3-Pa}{mol}}$$ $$m^3-Pa-mol^{-1}$$ -
$$HHV$$ - higher heating value $$\large{\frac{MMBtu}{lbm}}$$ $$\large{\frac{W}{m^2}}$$  $$W-m^{-2}$$ -
$$\sigma_h$$ sigma hoop stress $$\large{\frac{lbf}{in^2}}$$ $$Pa$$ $$kg-m^{-1}-s^{-2}$$ -
$$H$$ - horizontal cable force $$lbf$$ $$N$$ $$kg - m - s^{-2}$$ -
$$x$$ - horizontal distance $$ft$$ $$m$$ $$m$$ -
$$x$$ - horizontal distance from reaction to point on beam $$in$$ $$mm$$ $$mm$$ -
$$x$$ - horizontal position $$ft$$ $$m$$ $$m$$ -
$$R$$ - horizontal range of a projectile $$ft$$ $$m$$ $$m$$ -
$$H$$ - horizontal reaction load at bearing load $$lbf$$ $$N$$ $$kg - m - s^{-2}$$ -
$$HP$$, $$\;hp$$ - horsepower $$\large{\frac{lbf-ft}{sec}}$$ $$\large{\frac{J}{s}}$$ $$J-s^{-1}$$ -
$$HWD$$ - hot well depression - - - -
$$H_0$$ - Hubble constant - $$\large{\frac{1}{s}}$$  $$1-s^{-1}$$ $$2.25\;x\;10^{-18}$$ $$\large{\frac{1}{s}}$$
$$\omega$$ omega humidity ratio $$\large{\frac{lbm}{lbm}}$$ $$\large{\frac{kg}{kg}}$$ $$kg-kg^{-1}$$ -
$$k$$ - hydraulic conductivity $$\large{\frac{ft}{day}}$$ $$\large{\frac{m}{day}}$$ $$m-day^{-1}$$ -
$$h_d$$ - hydraulic depth $$ft$$ $$m$$ $$m$$ -
$$d_h$$ - hydraulic diameter $$ft$$ $$m$$ $$m$$ -
$$d_h$$  - hydraulic diameter of a duct, pipe or tube $$in$$  $$mm$$  $$mm$$  -
$$d_h$$  - hydraulic diameter of a rectangular tube  $$ft$$  $$m$$  $$m$$ -
$$d_h$$   - hydraulic diameter of a right triangle  $$ft$$  $$m$$  $$m$$  -
$$d_h$$ - hydraulic diameter of a square tube  $$in$$  $$mm$$  $$mm$$  -
$$d_h$$ - hydraulic diameter of a tube within a tube  $$in$$  $$mm$$  $$mm$$ -
$$d_h$$   - hydraulic diameter of an ellipse  $$in$$  $$mm$$  $$mm$$ -
$$d_h$$  - hydraulic diameter of an isosceles triangle  $$ft$$  $$m$$  $$m$$  -

$$n_h$$

hydraulic efficiency dimensionless     -
$$E_h$$ - hydraulic energy $$lbf-ft$$ $$J$$ $$kg - m^2 - s^{-2}$$ -
$$i$$ - hydraulic gradient dimensionless -
$$Q$$ - hydraulic gradient flow rate $$\large{\frac{ft^3}{sec}}$$ $$\large{\frac{m^3}{s}}$$  $$m^3-s^{-1}$$ -
$$h$$ - hydraulic head $$ft$$  $$m$$ $$m$$
$$HHP$$, $$\;HP_h$$ - hydraulic horsepower $$\large{\frac{lbf-ft}{sec}}$$ $$\large{\frac{J}{s}}$$ $$J-s^{-1}$$ -
$$P_h$$ - hydraulic power $$\large{\frac{lbm-ft^2}{sec}}$$ $$\large{\frac{kg-m^2}{s}}$$  $$kg-m^2-s^{-1}$$ -
$$n_h$$ - hydraulic pump efficiency dimensionless -
$$r_h$$ - hydraulic radius $$ft$$ $$m$$ $$m$$ -
$$r_h$$  - hydraulic radius of a partially full pipe (less than half full) $$in$$ $$mm$$  $$mm$$ -
$$r_h$$   - hydraulic radius of a partially full pipe (more than half full) $$in$$ $$mm$$ $$mm$$ -
$$r_h$$  - hydraulic radius of a pipe $$in$$ $$mm$$ $$mm$$ -
$$r_h$$   - hydraulic radius of a rectangular channel $$ft$$  $$m$$ $$m$$ -
$$r_h$$ - hydraulic radius of a trapezoidal channel (equal side slopes) $$ft$$ $$m$$ $$m$$ -
$$r_h$$  - hydraulic radius of a rapezoidal channel (unequal side slopes) $$ft$$ $$m$$ $$m$$ -
$$r_h$$   - hydraulic radius of a triangular channel $$ft$$ $$m$$  $$m$$ -
$$S$$ - hydraulic slope $$ft$$ $$m$$ $$m$$ -
$$H$$ - hydrogen density $$\large{\frac{lbm}{ft^3}}$$ $$\large{\frac{kg}{m^3}}$$  $$kg-m^{-3}$$ -
$$H$$ - hydrogen gas - - - -
$$HP$$ - hydrostatic pressure $$\large{\frac{lbf}{in^2}}$$ $$Pa$$ $$kg- m^{-1}-s^{-2}$$ -
$$HDS$$ - hydrostatic stress $$\large{\frac{lbf}{in^2}}$$ $$Pa$$ $$kg- m^{-1}-s^{-2}$$ -
hydrostatic weighting
$$\Delta \nu_{cs}$$  \nu hyperfine transition frequency of 133Cs $$Hz$$ $$Hz$$   $$s^{-1}$$  $$9\;192\;631\;770$$ $$Hz$$
Symbol Greek Symbol Drfinition English Metric   Value

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