ESDU Toolbox
IHS ESDU provides essential design methods and software for the aerospace, defence, transportation, energy and related industries. These methods and software are produced and rigorously validated in concert with the collective knowledge of hundreds of engineers from around the world.
Listed below are the ESDU 'Toolbox Apps'. These provide user friendly webbased interfaces to some ESDU programs. Some Toolbox Apps are only available to subscribers, others are freely available to subscribers and nonsubscribers alike.
Subscriber Toolbox Apps
See ESDU ASTEROID
Utilising Data Items ESDU 75031, ESDU 75028 and ESDU 74036.
ASTEROID
The ASTEROID program brings together the various ESDU methods for the calculation of excrescence drag due to steps, ridges, grooves and cavities on the external surfaces of aircraft. The app provides a simple interface that enables users to define the excrescences and then calculate the drag increments within a few minutes.
ASTEROID integrates the programs associated with ESDU 75031, ESDU 75028 and ESDU 74036 within the context of a specified and predetermined aircraft flow field. Multiple excrescence geometries can be specified on selected aircraft major components (i.e. a wing upper or lower surface, fuselage, nacelle, horizontal tail or fin). The app first asks the user to select an aircraft type (e.g. singleaisle transonic airliner, lowspeed commuter airliner, etc) from a list and to choose an appropriate cruise Mach number for consideration. The app then allocates the appropriate pregenerated local flow field so that typical flow conditions (including flow direction) at each excrescence can be determined. The flow data for the singleaisle and lowspeed commuter aircraft are presented for the whole airframe, together with a range of wings representative of short, medium and long range jet transports, and a blendedwing body design.
Excrescence geometries are then specified either as circular cavities or as multinode excrescences, which can be closed (e.g. to model a repair plate or cover) or open (e.g. to model a control surface gap). The edges of the excrescence can be characterised as steps (with or without edge treatments), rectangular or square ridges, grooves or gaps (with or without sealing).
When the excrescences have been defined, the app automatically selects the method from the appropriate Data Item and calculates the drag coefficients based on both the excrescence and aircraft reference areas. The aircraft drag coefficient penalty summed for all excrescences is also calculated.
Run ASTEROIDASTEROID fp
ASTEROID fp (flat plate) is a version of the ASTEROID drag prediction tool that uses the graphical and calculation modules (and data management capabilities) offered by the original program, but the user is freed from having to select one of the flowfields for specific aircraft or generic wings in the current database. Instead, all flow conditions are specified by the user, thereby extending ASTEROID's applicability, not only to aircraft whose airframes or components are not presently represented within the flowfield library, but also missiles, rockets, drones and nonaeronautical applications such as rail and road transports and wind engineering.
The designation 'fp' relates to the 'flat plate' condition, which is that addressed in all the excrescence drag calculation methods in the Aerodynamics Series' Data Items relating to specific excrescence types. Most of the windtunnel data were indeed for excrescence models mounted on flat plates but, in the wider context of applying such data to drag prediction, this should be interpreted as the drag in the absence of a pressure gradient. Therefore, no allowance is made in ASTEROID fp for any drag magnification that may be present, so that, in effect, the drag magnification factor is set to unity. The subject of excrescence drag magnification is discussed in detail in ESDU 90029.
Note that the use of ASTEROID fp is, in most respects, identical to ASTEROID, so the help files and instructional videos are applicable; the exception, of course, being references to the flowfield data library.
Run ASTEROID fpFrom Data Item ESDU Aero A.02.03.02.
This app determines the optimum area distribution and corresponding minimum theoretical transonic dragrise at zero lift. The program implements the method of ESDU Aero A.02.03.02, accessing the graphical data by use of the equations provided in the Data Item.
Run appFrom Data Item ESDU 74036.
This app implements ESDUpac A7436, which, in turn, is based correlations of experimental results obtained on a plate at zero incidence, for predicting the increment in drag for Mach numbers less than 3. The methods apply to a cavity with sharp edges, walls normal to the plate, flat bottom and no throughflow; no information is available on rounding or chamfering of the corners, but such edge modifications should not be assumed to be beneficial. The depth/diameter ratio varied from 0.04 to 1.5 but a method of dealing with a cavity in which the ratio is less than 0.04 and based on the method of ESDU 75031 is utilised. The data apply strictly in zero pressure gradient flows, but guidance on their use where there is a pressure gradient is given in the Data Item.
Run appFrom Data Item ESDU 75028.
ESDU 75028 is derived from a correlation of experimental data that enable the drag increment to be predicted due to a groove of planform aspect ratio greater than 8 normal to the flow. For grooves inclined at angles to the flow exceeding 60 degrees the data for the grooves normal to the flow apply, while for grooves inclined between 0 degrees (parallel to the flow) and 60 degrees a method for obtaining the maximum increment is suggested based on the use of ESDU 75031 to predict the increments due to the forward and rearwardfacing steps together with an appropriate skin friction allowance.
Run appFrom Data Item ESDU 75031.
ESDU 75031 gives an empirical method for the prediction of the drag increment due to a variety of twodimensional excrescences, each mounted normal to the flow direction on a flat plate, and immersed in a turbulent boundary layer for Mach numbers up to 3. The excrescence types are (1) a forwardfacing step, ramp (chamfered step), or a radiused step, (2) a rearwardfacing step, ramp (chamfered step), or a radiused step, and (3) a square section ridge or a rectangular section ridge (of height/length ratio 2), with or without radii to the top corners.
Run appFrom Data Item ESDU 20003.
ESDU 20003 provides crack resistance curves (Rcurves) for several aluminium, steel and titanium aerospace sheet materials in SI and British (lbf, in) units. The curves are indexed by alloy specification, details of which are given, together with relevant test conditions, in the Data Item. The Data Item includes a full description of the resistance curve concept, its application, advantages and limitations. The use of data determined from wide panel specimens is discussed. Two fully worked examples illustrate the use of the data to determine the onset of fast fracture. This Item supersedes ESDU 85031.
This Toolbox App is provided to interrogate the database of Rcurves according to material type, specification, heat treatment, orientation and additional criteria such as thickness and width. The output from the Toolbox App consists of a summary of the input data and a plot of the chosen Rcurve. The Δa' versus K_{R} coordinates of the Rcurve may be saved as either a CSV or a JSON file.
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International Standard Atmosphere app
This app determines, at a specified pressure altitude in the International Standard Atmosphere (ISA), absolute and relative values of pressure, temperature and density together with the absolute values of the speed of sound, kinematic and dynamic viscosity and thermal conductivity. It also determines V_{TAS}, V_{EAS}, kinetic pressure and unit Reynolds number for a specified Mach number at the given pressure altitude. Calculations are limited to the troposphere and stratosphere.
Section 4, of the ESDU Aerodynamics Series contains additional information on Atmospheres. In particular, for calculations at greater altitudes and for further details of the ISA consult ESDU 77021. A range of 'design' atmospheres that differ from the ISA is given in ESDU 78008.
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Wing liftcurve slope app from ESDU TM 169
This app employs a modified version of the HelmboldDiederich equation (described in ESDU TM 169) to estimate the liftcurve slope of a wing of trapezoidal planform. In order for the method to be applicable the wing must be thin and employ only moderate camber and twist, and the flow must remain both attached and wholly subcritical. Compressibility effects are catered for by means of the classic PrantlGlauert factor. The original HelmboldDiederich equation was often used before there was general access to more soundly based methods such as the liftingsurface theory (which is the basis of ESDU 70011). However, the improved and modified version of the equation used in this app provides estimates accurate to within a few per cent of those obtained by ESDU 70011, which itself has been assessed as providing estimates to within around 5% of windtunnel test data. The limits of applicability in terms of flow and geometric parameters for which the app produces results have been restricted to those cited for the method from ESDU 70011.
The full background to this method, and that of ESDU 70011, is given in ESDU TM 169 in the ESDU Aerodynamics Series.
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Skin friction coefficient on a flat plate
This App uses the semiempirical method of Spalding and Chi to obtain the local and mean skin friction coefficients for a turbulent boundary layer on a smooth flat plate with zero pressure gradient and zero heat transfer.
The data are applicable to flows with Reynolds numbers based on streamwise distance over the range 100 thousand to 1000 million and for Mach numbers up to 5.
The equations used are taken from Appendix A of ESDU 78019, which itself is based on the method described in ESDU 68020. Both of these Items are to be found in the Aerodynamics Series.
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Inelastic stressstrain curves from ESDU 89052
This app provides a method of estimating the stressstrain behaviour of a metallic material within the assumptions that this behaviour may be represented by a smooth continuous generalised curve. The method is valid for both tensile and compressive stressstrain data.
The curve is derived using the Young's modulus and two data points in the inelastic region (the tensile strength is used solely to limit the extent of the curve). The curve follows the modulus in the elastic region and in the inelastic region the greatest accuracy is in the region of the two data points used to derive the curve.
The two data points in the inelastic region may be given as either (a) two proof stresses and the corresponding permanent strains, or (b) two stresses and the corresponding total strains.
The theoretical basis for the generalised stressstrain form used by the app is detailed in ESDU 89052, 'Construction of inelastic stressstrain curves from minimal materials data', and ESDU 76016, 'Generalisation of smooth continuous stressstrain curves for metallic materials'.
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ESDU Series:
 Aerodynamics
 Aircraft Noise
 Composites
 Dynamics
 Fatigue  Endurance Data
 Fatigue  Fracture Mechanics
 Fluid Mechanics, Internal Flow
 Fluid Mechanics, Internal Flow (Aerospace)
 Heat Transfer
 Mechanisms
 Performance
 Physical Data, Chemical Engineering
 Stress and Strength
 Structures
 Transonic Aerodynamics
 Tribology
 Vibration and Acoustic Fatigue
 Wind Engineering
ESDU Packages: