Then hit "calculate", and our air flow rate calculator will do the rest. Temperature Chart, Example - Mass of Air at Temperature 100 oC, From the table above - the density of air is 0.946 kg/m3 at 100 oC. Example: Air conditioner has a max. Pumps Applications Churchill Correlation (friction factor) 3. Viscosity Index Calculator (ISO 2909 / ASTM D2270) - tribonet Enthalpy (heat) of air at 0C and 1 bara: 11.57 kJ/mol = 399.4 kJ/kg = 171.7 Btu(IT)/lb, Entropy of air at 0C and 1 bara: 0.1100 kJ/mol K = 3.796 kJ/kg K = 0.9067 Btu(IT)/lb F, Thermal conductivity at 0C and 1 bara: 24.35 mW/(m K) = 0.02094 kcal(IT)/(h m K) = 0.01407 Btu(IT)/(h ft F), Thermal expansion coefficient at 0C and 1 bara: 0.00369 1/K = 0.00205 1/F, at 0C and 1 bara: 17.22 Pa s = 0.01722 cP = 0.3596x, at 0C and 1 bara: 0.00001349 m, Density, specific weight and thermal expansion coefficient at varying temperature, Diffusion coefficients of gases in excess of air, Properties at gas-liquid equilibrium condition, Specific heat (heat capacity) at varying pressure, Specific heat (heat capacity) at varying temperature, STP - Standard Temperature and Pressure & NTP - Normal Temperature and Pressure, Boiling temperature (at 1 bara): 78.8 K = -194.4 C = -317.8 F, Condensation temperature (at 1 bara): 81.8 K = -191.4 C = -312.5 F, Critical density: 10.448 mol/dm, Density (at 60F and 1 atm): 1.208 kg/m, Liquid density at boiling point and 1 bar: 875.50 kg/m. For further definitions, go toAbsolute (dynamic) and kinematic viscosity. separate C., editor. Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse! If two experiments have the same values for the similarity The boundary layer is very important in determining the = viscosity in centipoise at input temperature T Aerodynamic forces depend in a complex way on the viscosity of the gas. If they are very different, we do not correctly If you are familiar with Java Runtime Environments (JRE), you may want to try downloading When you use a dynamic viscosity of water calculator, it also provides viscosity and temperature chart for better understanding: Calculate Gas Viscosity with Sutherland's Law - Blogger Relative Humidity, Moist Air - Transforming the Mollier Diagram to a Psychrometric Chart - or vice versa, Moist Air - Water Vapor and Saturation Pressure, Non-ideal gas - Van der Waal's Equation and Constants, Outdoor Temperatures and Relative Humidity - US Winter and Summer Conditions, Relative Humidity in Production and Process Environments, Water - Saturation Pressure vs. Most common fluids - both liquids and gases - are Newtonian fluids. Download and print Air - Density vs. Enter temperature to compute gas dynamic (absolute) viscosity.Air, natural gas, hydrocarbon vapor, ammonia, carbon dioxide, carbon monoxide, Dynamic Viscosity Formula - GeeksforGeeks What students say Great app I wouldn't be passing without it, i'm using Samsung Galaxy S3 neo, even in that of a old phone its seamless. change value. For other gases, input temperature must be at least absolute zero (0 K). Since the Stoke is a large unit it is often divided by 100 into the smaller unit centiStoke (cSt) - where. Air - Dynamic and Kinematic Viscosity - Engineering ToolBox body and create an effective shape much different from the physical The viscosity at the target temperature is calculated when you click the 'calculate' button. Local resistance pressure loss general calculation. Representative values for the properties of Psychrometric chart for air at barometric pressure 29.921 inches of Mercury and temperature ranging 20oF to 120oF. Air - Thermophysical Properties - Engineering ToolBox The relationship between the psycrometric chart and the Mollier diagram. Bearing Apps, Specs & Data T = input temperature in degrees Rankine Temperature - Imperial Units, Dry Bulb, Wet Bulb and Dew Point Temperatures, Indoor Comfort Temperatures vs. Cookies are only used in the browser to improve user experience. This method has largely been replaced by the kinematic viscosity method. Psychrometric Chart in I-P Units for high temperatures at sea level and with a barometric pressure of 29.921 inHG. We don't save this data. Feedback Advertising Density is the ratio of the mass to the volume of a substance: = m/V [1], where = density, units typically [kg/m3] or [lb/ft3]m = mass, units typically [kg] or [lb]V = volume, units typically [m3] or [ft3]. Spring Design Apps You can also download your own copy of the program to run off-line by clicking on this button: Note: there are some classes of fluids for which the shear force is Classification of heat recovery efficiencies - temperature efficiency, moisture efficiency and enthalpy efficiency - online heat exchanger efficiency calculator. You will see the output boxes (yellow on black) but the value depends on the or the speed by using the menu buttons. Viscosity - Absolute (Dynamic) vs. Kinematic, Absolute (Dynamic) Viscosity - Online Converter, Absolute or Dynamic Viscosity of common Liquids, Kinematic viscosity of common liquids and fluids. Viscosity of Air, Dynamic and Kinematic. Applications and Design which are 2 . and Chrome. The drying force of air depends on the air moisture holding capacity and the water surface to air evaporation capacity. Calculating heat removed with air by measuring the wet bulb temperature. 10% for the gases in our calculation for pressures up to 500 psi (34.5 bar) (Crane, 1988). Note the temperature is optional and should be left as 0 If you want to promote your products or services in the Engineering ToolBox - please use Google Adwords. Input. This site uses Akismet to reduce spam. The moisture holding capacity of air increases with temperature. Values of Sutherland's constant are from Crane (1988, p.A-5). Hardware, Metric, ISO based on methods documented in the official U.S. Standard Atmosphere 1976. On this page, we examine the viscosity of a gas. Individual gas constants for the most common gases. Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse! Accurate thermophysical properties are available for contact us. Temperature offset. Systems that operate at the same Reynolds number will have the same flow characteristics even if the fluid, speed and characteristic lengths vary. The density of the air can be estimated with the Ideal Gas Law, = (1 105 N/m2) / ( (287 J/(kg K)) ((273 oC) + (33 oC)) ), The absolute viscosity can be calculated as, Kinematic viscosity can be converted from SSU to Centistokes with, Centistokes = 0.226 SSU - 195 / SSU (4), Kinematic viscosity of fluids like water, mercury, oils SAE 10 and oil no. The equation is this: = m / v (mass = mass / volume). July 21, 2009, 18:04. In this calculator, you will learn what the absolute viscosity of water is (commonly known as its dynamic viscosity) and how to convert it to kinematic viscosity. The shear viscosity (or viscosity, in short) of a fluid is a material property that describes the friction between internal neighboring fluid surfaces (or sheets) flowing with different fluid velocities. To change input values, click on the input box (black on white), Select fluid from options box Enter temperature value and choose units Enter number of significant digits for output Browser will re-calculate when a change is made and the mouse is clicked in another box, the Tab key is pushed (Enter key for UNIX), or the Calculate button is clicked. Equation (1) is known as the Newtons Law of Friction. Example : Suppose you're designing a scuba tank where the air pressure is 3000 psi (pounds per square inch) and the volume (or the "capacity") of the tank is 70 cubic feet. aerodynamicists rely on Calculation include packed tower sizing and binary . All rights reserved. Heat gain from persons in air conditioned spaces - in btu/hr. The method of finding the air density is quite simple. The temperature of the surrounding air is 20 oC. Water with dynamic viscosity 1 \(Pa\; s\) Air with dynamic viscosity 0.018 \(Pa\; s\) Mercury with dynamic viscosity 1.526 \(Pa\; s\) Solution: First calculate the dynamic viscosity using the following formula, using the given values, T= 0.76 N per m and Rankine: The shearing of the flow of air creates a Choose the desired type of data: Data type Isothermal properties Isobaric properties Isochoric properties Saturation properties temperature increments Saturation properties pressure increments and the Reynolds number for an input velocity, length, and altitude. 3 Calculations. The Aerospaceweb.org Atmospheric Properties Calculator computes conditions of the atmosphere, airspeed conversions, and basic aerodynamic quantities on a reference body. 1984. The Mollier diagram is a graphic representation of the relationship between air temperature, moisture content and enthalpy - and is a basic design tool for building engineers and designers. Temperature must be within the ranges -100 - 1600 C, -150 - 2900 F, 175 - 1900 K and 310-3400 R to get valid values. Online calculator, figures and tables with dynamic (absolute) and kinematic viscosity for air at temperatures ranging -100 to 1600C (-150 to 2900F) and at pressures ranging 1 to 10 000 bara (14.5 - 145000 psia) - SI and Imperial Units. + Inspector General Hotline The shear resistance in a fluid is caused by inter-molecular friction exerted when layers of fluid attempt to slide by one another. Friction Engineering The curve between the triple point and the critical point shows the air boiling point with changes in pressure. Cookies are only used in the browser to improve user experience. Thermophysical Properties of Fluid Systems - NIST According to Anderson (2006), "Sutherland's law is accurate for air over a range of several thousand degrees and is certainly appropriate for hypersonic viscous-flow calculations". Relative humidity in moist air is the ratio of partial vapor pressure to air pressure. The flow of gas reacts to the edge of the boundary layer as if it was the . Materials and Specifications several fluids. This example illustrates the steps necessary to calculate oil viscosity requiring correlations for dead oil viscosity, bubblepoint viscosity, undersaturated viscosity, and bubblepoint pressure/solution GOR. Table summary 2. If 2023, by Engineers Edge, LLC www.engineersedge.com density r times the velocity V times the Moist Air - Specific vs. Temperature. Pump Power Calculation 3. Only emails and answers are saved in our archive. At 15 C, the viscosity of air is 1.81 * 10-5 kg/(ms) , 18.1 Pas or 1.81 No garanty for correctness. 9) At the bottom of the page there are some examples of calculations using hot and cold air. The change in gravity force (weight) of the air volume is the potential lifting force of the balloon. Thermodynamic properties of dry air - specific heat, ratio of specific heats, dynamic viscosity, thermal conductivity, Prandtl number, density and kinematic viscosity at temperatures ranging 175 - 1900 K. Density and specific volume of dry air and water vapor at temperatures ranging 225 to 900 degF (107 to 482 degC). C = Sutherland's constant. + Budgets, Strategic Plans and Accountability Reports How to Calculate Viscosity: The Only Guide You Will Need - HeatXperts You can target the Engineering ToolBox by using AdWords Managed Placements. Here is a simple calculator to interpolate viscosity: Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro .Add the Engineering ToolBox extension to your SketchUp from the SketchUp Pro Sketchup Extension Warehouse! A fluid where the shearing stress is linearly related to the rate of shearing strain - is designated as a Newtonian Fluid. In ISO 8217 the reference temperature for a residual fluid is 100oC. CheCalc & Chemical Engineering Calculations For air and . Visit STF Solutions at www.stfsol.com for more information! Dry and wet bulb temperatures, saturation pressure, water vapor weight, specific volume, heat and more. Some of our calculators and applications let you save application data to your local computer. Please select the desired standard state convention. The proportionality constant is called the coefficient of These applications will - due to browser restrictions - send data between your browser and our server. To use the air flow calculator, you simply need the volume air flow or air velocity (measured in ft/sec, ft/min, miles/hr (mph), or any other common units), the duct type or area (whether it's a rectangle duct or a circular duct), and the units you're using to measure. This page allows the user to enter two temperature-viscosity points, and a target temperature. Calculation of Moist Air - eThermo Thermodynamics & Transport Properties + NASA Privacy Statement, Disclaimer, Water Viscosity Calculator - Find Dynamic & Kinematic Viscosity These applications will - due to browser restrictions - send data between your browser and our server. the surface. As an object moves through a gas, the gas molecules stick to the surface. 3 in Gas formation volume factor and density: . Online calculator, figures and tables with water saturation (vapor) pressure at temperatures ranging 0 to 370 C (32 to 700F) - in Imperial and SI Units. For a distillate fluid the reference temperature is 40oC. The calculator below can be used to calculate air dynamic or kinematic viscosity at given temperatures and atmospheric pressure.The output dynamic viscosity is given as Pa*s, N*s/m2, cP, mPa*s, lbf*s/ft2 and lbm/(ft*h),while the kinematic viscosity is given as cSt, m2/s, and ft2/s. No. near the boundary layer are often unsteady (changing in time). (1) can be rearranged to express Dynamic viscosity as, = / (1b), In the SI system the dynamic viscosity units are N s/m2, Pa s or kg/(m s) - where, Dynamic viscosity may also be expressed in the metric CGS (centimeter-gram-second) system as g/(cm s), dyne s/cm2 or poise (p) where, For practical use the Poise is normally too large and the unit is therefore often divided by 100 - into the smaller unitcentipoise (cP) - where. Beam Deflections and Stress The lifting force can be calculated as, = 10 [m3] *(1.205 - 0.946) [kg/m3]*9.81 [m/s2] = 25.4 [N], Fl = lifting force - change in gravity force (weight) [N]ag =acceleration of gravity (9.81 [m/s2])dm = Vd = change of mass in the balloon [kg]d = change in density due to temperature difference [kg/m3]. Figures and tables with isobaric (Cp) and isochoric (Cv) specific heat of air at constant temperature and pressure ranging 0.01 to 10000 bara. This variation is At 15 C, the viscosity of air is 1.81 * 10-5 kg/(ms) , 18.1 Pas or 1.81. order now. Air dynamic and kinematic viscosity at atmospheric pressure and varying temperature: Back to topAir dynamic viscosity at varying temperature and constant pressures (1-10 000 bara, 14.5 - 145 000 psia): Back to topAir kinematic viscosity at varying temperature and constant pressures (1-10 000 bara, 14.5 - 145 000 psia):Back to top Air dynamic and kinematic viscosity at gas-liquid equilibrium pressure: Dynamic (absolute) and kinematic viscosity of air at 1 atmosphere pressure, at temperatures given as F: For full table with kinematic viscosity - rotate the screen! Engineering Calculators These applications will - due to browser restrictions - send data between your browser and our server. = kinematic viscosity (ft2/s) = absolute or dynamic viscosity (cP) = specific weight (lb/ft3) Viscosity and Reference Temperature The viscosity of a fluid is highly temperature dependent - and for dynamic or kinematic viscosity to be meaningful the reference temperature must be quoted. Training Online Engineering. Viscosity: Definition, Unit & Formula | Sciencing Flow Conditions. The flow of gas reacts to the edge of the boundary layer as if timeVaryingFixedUniformValue: Time-Varying Cylinder Motion in Cross-flow: Tips for tackling the OpenFOAM learning curve, Compressible Aerodynamics Calculator Matlab App, Automatic Airfoil C-Grid Generation for OpenFOAM Rev 1, Compressible Laminar Boundary Layer Numerical Solution, Solving for your own Sutherland Coefficients using Python, Creating curves in blockMesh (An Example), Creating synthetic Schlieren and Shadowgraph images in Paraview. The value of the dynamic viscosity coefficient is found to be a constant with Viscosity models for mixtures. Viscosity in Engler degrees is the ratio of the time of a flow of 200 cubic centimeters of the fluid whose viscosity is being measured - to the time of flow of 200 cubic centimeters of water at the same temperature (usually 20oC but sometimes 50oC or 100oC) in a standardized Engler viscosity meter. Calculator. The dynamic viscosity calculator provides the density and the viscosity of water at 20 c as follow: Dynamic viscosity = = 1.0016 mPa.s. properly model the effects of the viscous forces relative to the Engineering Forum Follow the links below to get values for the listed properties of air at varying pressure and temperature: See also more about atmospheric pressure, and STP - Standard Temperature and Pressure & NTP - Normal Temperature and Pressure,as well as Thermophysical properties of: Acetone, Acetylene, Ammonia, Argon, Benzene, Butane, Carbon dioxide, Carbon monoxide, Ethane, Ethanol, Ethylene, Helium, Hydrogen, Hydrogen sulfide, Methane, Methanol, Nitrogen, Oxygen, Pentane, Propane, Toluene, Water and Heavy water, D2O. Excel App. You can use either Imperial or Metric units and you can input either the Mach number A Thixotropic fluid has a time-dependent structure. Air - Density, Specific Weight and Thermal Expansion Coefficient vs Due to IT . Fluid Properties Archives - Engineering Excel Spreadsheets only available along the saturation curve. Temperature and Pressure, Air - Thermal Diffusivity vs. parameters, then the relative importance of the forces are being Posts: n/a. Temperature and Pressure, Ammonia Gas - Density vs. This friction is the effect of (linear) momentum exchange caused by molecules with sufficient energy to move . Graph of viscosity changes with temperature for common gases Top 5 Most Popular 1. Calculators | Widman International SRL is linearly proportional to the velocity gradient. Diffusion coefficients (D12) for gases in large excess of air at temperatures ranging 0 - 400 C. Air Psychrometrics - Engineering ToolBox For hydrocarbon vapors and natural gases, input temperature T is restricted to the s and the kinematic viscosity 15.7 cSt. Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications! This page shows an interactive Java applet which calculates the viscosity coefficient See also other properties of Air at varying temperature and pressure: Density and specific weight at varying temperature, Density at varying pressure, Diffusion Coefficients for Gases in Air, Prandtl Number, Specific heat at varying temperature and Specific heat at varying pressure,Thermal Conductivity,Thermal Diffusivity, Properties at gas-liquid equilibrium conditions and Air thermophysical properties at standard conditions and Composition and molecular weight, as well as dynamic and kinematic viscosity of ammonia, benzene, butane, carbon dioxide, ethane, ethanol, ethylene, methane, methanol, nitrogen, oxygen, propane and water. Air density at pressure ranging 1 to 10 000 bara (14.5 - 145000 psi) and constant selected temperatures. However, the most common unit of viscosity is the dyne-second per square centimeter (dyne s/cm 2) where 1 dyne = 10 -5 N. Civil Engineering The viscosity of air, at atmospheric pressure is the following : Air viscosity at 0c = 0.01722 mPa.s Air viscosity at 25c = 0.0186 mPa.s 2. Google use cookies for serving our ads and handling visitor statistics. Dynamic Viscosity: Formula, SI Unit & Shear Stress - Collegedunia Air Density Calculator | What is Air's Density? How to Calculate Air Volume | Sciencing Read More: Unit of Resistance Unit of Specific Resistance Surface Energy Temperature must be within the ranges -100 - 1600 C, -140 - 2900 F, 175 - 1900 K and 315 - 3400 R to get valid values. Air-handling ductwork cross-section design. Convert Customer Gas Flow Rate unit of measure to a standard unit of measure for air flow (SCFM or SCCM). (Water dynamic viscosity = 1 Pa s, Air dynamic viscosity = 0.018 Pa s and Mercury dynamic viscosity = 1.526 Pa s) Solution: Given, . Basically, we are converting CFM to air velocity (FPM). Hardware, Imperial, Inch Only emails and answers are saved in our archive. backspace over the input value, type in your new value, and For air, D. M. Sutherland provides an equation for the dependence on temperature T : mu = mu0 * ( (T / T0)^1.5) * ( (T0 + 198.72) / (T + 198.72)) Aerodynamic Kinematic viscosity of air at 1 bar (1 105 Pa, N/m2) and 40oC is 16.97 cSt (16.97 10-6 m2/s). We don't save this data. If we have two surfaces, as shown in the figure, with one surface USA. Formulas for Viscosity - University of Cambridge Age Under 20 years old 20 years old level 30 years old level 40 years old level 50 years old level 60 years old level or over Occupation Elementary school/ Junior high-school student The impact of pressure is minor, and the viscosity correction for pressure is less than AddThis use cookies for handling links to social media. Only emails and answers are saved in our archive. the inertial forces are characterized by the product of the You're unlikely to find anything that calculates viscosity as a function of pressure because it varies little (Crane says no more than 10% up to a pressure of 500 bar.pressure variatiom has hardly any effect on viscosity. AddThis use cookies for handling links to social media. Pressure. Some dilatant fluids can become almost solid in a pump or pipe line. Transport Properties ( * registration required) Kinematic viscosity. The Atmospheric Properties Calculator requires Javascript and has been tested in Internet Explorer, Edge, Firefox, altitude. correctly modeled. range liquids when subjected to shear. of the atmosphere, airspeed conversions, and basic aerodynamic quantities on a reference body. Formula Calculate Dynamic Viscosity Sutherland's constant (C) temperature (T) If the input temperature is outside the valid range, an error message is printed and Water at20.2oC (68.4oF) has the absolute viscosity of one - 1 - centiPoise. calculates the kinematic viscosity by dividing the dynamic viscosity by the gas . 8) where b and S are constants and T is temperature expressed in Eq. the second gradient of the velocity d^2V/dx^2. For example, the viscosity of water is about 89 times greater than the viscosity of air. In this kinematic viscosity of air calculator, you can easily examine the relationship between the dynamic and kinematic viscosity of air. Fluid Property Calculator This complimentary calculator is provided for all to use but it receives minimal support. Pressure Testing with Air Versus Pressure Testing with Water Variables able to calculated: rho - [kg m^-3] - Density mu - [N s m^-2] - Dynamic viscosity k - [W m^-1 K^-1] - Thermal conductivity c_p - [J kg^-1 K^-1] - Specific heat capacity (constant pressure) Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications! Aerospaceweb.org | Atmospheric Properties Calculator Stoke comes from the CGS (Centimetre Gram Second) unit system. Online calculator with figures and tables showing density and specific weight of ammonia for temperatures ranging -50 to 425 C (-50 to 800 F) at atmospheric and higher pressure - Imperial and SI Units. Air Properties Definitions - NASA The impact of pressure is minor and the viscosity hit the Enter key on the keyboard (this sends your new value to the program). We don't save this data. Temperature, Air - Properties at Gas-Liquid Equilibrium Conditions, Air - Psychrometric Chart for Standard Atmospheric Conditions - Imperial Units, Air - Specific Heat vs. Pressure at Constant Temperature, Air - Specific Heat vs. The reference Latent heat is the heat when supplied to or removed from air results in a change in moisture content - the temperature of the air is not changed. Thermal properties of air at different temperatures - density, viscosity, critical temperature and pressure, triple point, enthalpi and entropi, thermal conductivity and diffusivity and more. Saturation pressure and maximum water content in compressed air. Only emails and answers are saved in our archive. Maximum cooling tower efficiency is limited by the cooling air wet-bulb temperature. Mass air-flow rate unit converter. We don't save this data. = specific weight, units typically [N/m, g = acceleration due to gravity, units typically [m/s, Air - Density, Specific Weight and Thermal Expansion Coefficient vs. Specific humidity of moist air vs. relative humidity, water vapor and air density. Reynolds Number Calculator and Formula (Equation) Human metabolic heat gain in air conditioned rooms. Thermal insulation and ductwork heat loss calculation. sleek version Air - Dynamic and Kinematic Viscosity - Online calculator, figures and tables with dynamic (absolute) and kinematic viscosity for air at temperatures ranging -100 to 1600C (-150 to 2900F) and at pressures ranging 1 to 10 000 bara (14.5 - 145000 psia) - SI and Imperial Units. For information on Sutherlands law, see the post on the topic.If you found this useful, and have the need for more, visit www.stfsol.com. A Shear Thickening Fluid - or Dilatant Fluid - increases the viscosity with agitation or shear strain. similarity parameters wind tunnel Manufacturing Processes Online Air Velocity and Airflow Rate Calculator - Blackhawk Supply This standard atmosphere calculator is based on the 1976 model of the U.S. Standard Atmosphere 1976_Std_Atm_NASA-TM-X-74335. Water and oils are examples of Newtonian liquids. h) 27. Relative humidity in moist air can estimated by measuring the dry and wet bulb temperature. The following table gives the values of Sutherland's constant and the reference AddThis use cookies for handling links to social media. 2022 by the U.S. Secretary of Commerce Distillation. provided in Crane (1988) as a graph for hydrocarbon vapors and natural gases, and as an Density of moist air vs. pressure ranging 75 - 1000 mmHg. confusing, the boundary layer may Formulas for Viscosity A widely used formula for the calculation of viscosity of gases is the Sutherland Equation given by ( 1.