ZAERO New Features

The following sections present the enhancements that have been made to the ZAERO software system beginning with version 4.3 (original release in July 2002).

ZAERO Software System Enhancements/Upgrades

Version 8.4

Version 8.4 Enhancements

Starting from ZAERO Version 8.4, the default aerodynamic center on each aerodynamic box of lifting surfaces (CAERO7) at subsonic Mach numbers have been changed from 50% mid-chord to 25% mid-chord. It has been found that by changing the aerodynamic center from 50% mid-chord to 25% mid-chord on each aerodynamic box gives better agreement of the aeroelastic solution with that of the Doublet Lattice method. Consequently, results computed by ZAERO Version 8.4 at subsonic Mach numbers (specified by the MKAEROZ bulk data card) are slightly different from those computed by earlier versions of ZAERO. If you wish to obtain the results of previous versions (prior to versions 8.4), you must specify a new Executive Control Command called "SUBAC50" in the Executive Control Command section. The SUBAC50 executive control command has no effect on supersonic/hypersonic flow conditions. Since the change of the aerodynamic center location has no effect on the Aerodynamic Influence Coefficient (AIC) matrices, any AIC's you may have saved previously by earlier versions can still be used in re-start runs. The results of all subsonic test cases in the Applications Manual have been updated to reflect the new 25% mid-chord results.
A new entry called CURV has been added in the SPLINE2 bulk data card with a default of CURV=1.0 to include the curvature effect of the torsion stiffness of the beam. This effect is not included in the SPLINE2 card of MSC.Nastran. If you wish to get identical results between the SPLINE2 of MSC.Nastran and ZAERO, you must specify CURV=0.0.

Version 8.3 Enhancements

The wing thickness distribution on the CAERO7 macroelement can now be viewed by specifying a negative identification number on the PLTAERO bulk data card. This wing thickness distribution is represented by wing aerodynamic boxes placed on the wing upper and lower surfaces.
The maximum number of body segments can be specified in the BODY7 bulk data card was limited to 27 segments. In version 8.3, the number that can be specified is unlimited.
A bug was found of the MLDCOMD bulk data card (in the EXTINP entry) whenever it refers to a GRIDFRC bulk data card. This bug caused a wrong pointer to be used that could lead to incorrect results.
The AEROZ bulk data card has been modified to turn off the FMMUNIT entry. Inputting mass and length units has caused significant confusion among users in the past. In this light, the program will now automatically assign "N/" or "LBF/" to the FMMUNIT based on whether metric or English units are specified on the FMLUNIT entry, respectively.
Correlation coefficients of cross power spectrum density due to continuous gust are calculated and printed out in the standard output.
LABEL = “LOADMOD1” option is added in the TRIMFNC bulk data card to compute the section loads due to trim using summation of forces method. This option can provide more accurate section loads than that of the LABEL = “LOADMOD” option.
Many ZAERO Modules such as TRIM, MLOADS, NLFLTR…etc. requires the structural G-set mass matrix to compute the inertial loads. To export this matrix form MSC.Nastran needs the DMAP ALTER statement to be specified in the Nastran input deck. Because the DMAP sequence of MSC.Nastran may be version-dependent, a typical DMAP ALTER statement that can export the G-set mass matrix (MGG) and other matricies such as MGH, KGH, and KGG from all versions of MSC.Nastran is provided as follows:

assign output4='fw_fct_000.smgh' status=unknown unit=11 form=formated
assign output4='fw_fct_000.smgg' status=unknown unit=12 form=formated
assign output4='fw_fct_000.skgh' status=unknown unit=13 form=unformated
assign output4='fw_fct_000.skgg' status=unknown unit=17 form=unformated
SOL 103
COMPILE SEMODES SOUIN=MSCSOU NOLIST $
ALTER 'STRAIN ENERGY'
MATGEN EQEXINS/INTEXT/9//LUSETS $ GENERATE EXTERNAL SEQUENCE MATRIX
MPYAD KGG,PHG,/MKHINT $ MKHINT IS THE MKH IN INTERNAL SEQUENCE
MPYAD INTEXT,MKHINT,/KGH $ TRANSFORM MKHINT TO EXTERNAL SEQUENCE
MPYAD MGG,PHG,/MGHINT $ MGHINT IS THE MGH IN INTERNAL SEQUENCE
MPYAD INTEXT,MGHINT,/MGH $ TRANSFORM MGHINT TO EXTERNAL SEQUENCE
OUTPUT4 MGH//-1/11/2 $ OUTPUT MGH TO UNIT=11 IN fw_fct_000.smgh
OUTPUT4 MGG//-1/12/2 $ OUTPUT MGG TO UNIT=12 IN fw_fct_000.smgg
OUTPUT4 KGH//-1/13/2 $ OUTPUT KGH TO UNIT=13 IN fw_fct_000.skgh
OUTPUT4 KGG//-1/17/2 $ OUTPUT KGG TO UNIT=17 IN fw_fct_000.skgg
ENDALTER
CEND

Version 8.2 Enhancements

A new module called the IADS module has been developed to output required data on an external file for running the ZONA Technology developed IADS ActiveX control called the ZONA-IADS Aeroelastic Model Simulator (ZAMS). The Interactive Authoring Display System (IADS) is a real-time and post-time display and analysis software suite, developed by Symvionics, Inc., that supports multi-discipline testing. The software provides a wide range of displays that cover all flight test control room disciplines. To activate the IADS module, the user must specify a new case control command called IADS that refers to a new bulk data card called IADS.

Version 8.1 Enhancements

Two new modules have been added to perform an asymmetric flutter analysis using only a half model; namely, (a) an Asymmetric Flutter Module (FLTASYM), and (b) an Asymmetric Parametric Flutter Module (AFLTPRM). These two modules are very useful for a flutter analysis of aircraft that have asymmetric store configurations.
A new bulk data card called FLTASYM is added into the bulk data card section. The FLTASYM bulk data card is similar to the FLUTTER bulk data card except that it requires both symmetric and antisymmetric modal solutions to construct an asymmetric modal solution. To activate the FLTASYM bulk data card, a new Case Control Command called FLTASYM has been added that refers to a FLTASYM bulk data card.
Analogous to (2) above, a new bulk data card called AFLTPRM and associated new Case Control Command called AFLTPRM have been added.

Version 8.0 Enhancements

The ZAERO packaging has been modified from its earlier format to allow for more compact delivery to the end user. The manuals have been reduced in size and are now hard bound.
A new bulk data card called DFS has been added to export data to an external file that will be the input file of the Dynamic Flight Simulation Software. The Dynamic Flight Simulation Software is a ZONA product that can include the flexibility effects into the six degree-of-freedom simulator for rigid body. Please contact ZONA Technology to obtain more information on the Dynamic Flight Simulation Software or to license this option.
The following new options have been added to the INPCFD bulk data card:
(a) The CFD solution in the PLOT3D format can be either formatted, unformatted, or binary.
(b) The CFD solution can be normalized on three options; density, speed-of-sound, pressure, and velocity.
(c) Support for big and little endian has been incorporated allowing for a CFD file generated on a UNIX machine (such as the SGI) to be directly read by ZAERO running on a PC/Windows machine.
A Fast Fourier Transform (FFT) technique has been added in the gust module to accelerate the numerical integration of the Fourier Transform. This FFT technique can be activated by specifying negative frequency steps (i.e., the entry DF<0.0) in the CGUST or DGUST bulk data cards.
The and N0, where is the ratios of indicated response RMS to the gust RMS and N0 is the number of crossings of the RMS value, have been calculated and are output in the standard output file for a continuous gust analysis (i.e., GLOADS discipline).

Version 7.4 Enhancements

A gust sensor capability has been added in the Gust Module that allows the sensing of the gust velocity for gust load alleviation in a closed-loop gust analysis. This can be done by specifying a GUSTINP bulk data card that is referred to by a GLOADS bulk data card.
A matched filter methodology has been incorporated into the Gust Module that can determine the worst case discrete gust profile. A new case control command called MFTGUST and a new bulk data card also called MFTGUST have been added. The MFTGUST case control command refers to the MFTGUST bulk data card to activate the computation of the matched filter methodology. The output is a worst case discrete gust profile that gives a maximum response of user specified component loads, grid point acceleration, grid point displacement, etc.
A “restart” capability has been added to the GLOADS bulk data card that saves or retrieves the inverse of the frequency domain system matrix. This “restart” option can save significant computational time for multiple frequency domain gust analyses for different gust profiles but with the same system matrix.
An UNFORMATTED option has been added to the OUTPUT4 bulk data card that allows one to export matrices in an unformatted (binary) file.
A new bulk data card called OMITMOD has been added to allow for the permanent deletion of structure modes from the database. All ZAERO engineering analyses (i.e., subcases) are performed using the remaining structure modes if the OMITMOD bulk data card is used.
An NX Nastran option has been added to the ASSIGN FEM= executive control command so that NX Nastran standard output files (*.f06) can now be read in and processed by ZAERO’s FEM module.

Version 7.3 Enhancements

The FLUTTER and the FLTPRAM engineering modules have been parallelized. The computations within these modules can now be performed over multiple CPUs. A new Executive Control Command (“CPU n”, where n = no. of CPU’s) can be used to activate the parallel feature within these modules. To run parallel version of ZAERO, MPI (Message Passing Interface) needs to be installed. Note that the current parallel version of ZAERO can only be run on a single machine with multiple CPU’s.
The PATRAN plot file output option has been extended to generate a PATRAN session file. The session file can be loaded directly into PATRAN that will automatically load the generated neutral file (containing the aerodynamic model), all of the results files, and automatically launch the animation process within PATRAN. Note that one results file is generated for each time step for both the flutter mode (PLTFLUT bulk data card) and transient response output (PLTTIME bulk data card). Since this process can potentially yield a large number of results files, loading them into PATRAN one at a time becomes very cumbersome. This new feature greatly relieves the user burden. (Please see Chapter 7.0 for details)
The Femap plot file output option has been corrected for the flutter mode (PLTFLUT bulk data card) and transient response output (PLTTIME bulk data card). ZAERO now outputs one output set to the Femap neutral file for each time step. The Animate Multi-Set option from the View/Select window can now be used to correctly animate the flutter mode and transient response results. (Please see Chapter 7.0 for details)
The description of the MININP bulk data card has been modified to describe how to replace the coefficients in the rational function approximation matrices by user-supplied values. It also shows how to include gravity terms and the change of force and moment due to the change in forward speed in the rational function approximation so that the phugoid mode can be properly computed by the ASE analysis.
A new option has been added to the SOF entry of the MLDPRNT bulk data card. This new option allows you to specify SOF=RFA which triggers ZAERO to compute the dynamic loads using the mode acceleration method with the aerodynamic forces computed using the rational function approximation. Note that the SOF=YES option also uses the mode acceleration method but with aerodynamic forces computed by the inverse Fourier transform.
A new bulk data card INPCFD1 has been added to allow the ZTRAN method to read in the unstructured CFD solutions. The user must first convert the output from their unstructured CFD code to the format defined by INPCFD1 bulk data card to use this feature.

Version 7.2 Enhancements

The enforcement of zero eigenvalue for rigid body modes in the state space matrix assembled by the ASE module is now only activated if an RBRED bulk data card is specified. This enforcement process was activated in the earlier versions of ZAERO if either the SUPORT entry in the “ASSIGN FEM=” Executive Control Command or an RBRED bulk data card was specified and ensures that the number of zero eigenvalues of the state space matrix is equal to the number of rigid body modes. Otherwise, a small but unstable eigenvalue may appear due to numerical truncation error resulting from the Rational Function Approximation. RBRED affects the following modules: ASE, GLOADS, ELOADS, MLOADS, and NLFLTR. For those modules that involve rigid body modes, if an input deck contains a SUPORT entry but without RBRED, may give different results between version 7.2 and earlier versions of ZAERO. To get the older results back, you must add an RBRED card.

Due to this change, the bulk data card description of the RBRED has been changed.

The SUPORT entry in the “ASSIGN FEM=” Executive Control Command now only cleans-up the mode shape of the rigid body modes. Please see Remark 10 of the “ASSIGN FEM=” Executive Control Command for details on the SUPORT entry.
An “ADD” option has been incorporated in the SAVE entry of the MKAEROZ bulk data card. This allows the user to insert new reduced frequencies to a previously saved AIC file. Please see the MKAEROZ bulk data card description for details.
A new bulk data card called RBQHH has been developed that allows for the replacement of the generalized aerodynamic forces of the rigid body mode by user imported aerodynamic stability derivatives. This ensures that the eigenvalues of the rigid body modes, such as short period and phugoid modes, etc., can be captured by the FLUTTER and ASE modules.
An error in the NLSYSM bulk data card has been corrected. The incorrect equations of motion shown in Remark 6 of the NLSYSM bulk data card in the ZAERO User's Manual was as follows:

The sign on the right hand side of the first and last equation has been changed to:

Back to top

Version 7.1 Enhancements

The data structure of the saved Aerodynamic Influence Coefficient (AIC) file has been changed to improve the “read back” speed. The AIC’s are saved when setting the SAVE entry of the MKAEROZ bulk data card to SAVE. Saved AIC files prior to ZAERO version 7.1 cannot be reused with this latest version. Therefore, all AIC files generated with earlier versions of ZAERO must be re-generated using version 7.1 or higher.
The continuous gust analysis has been removed from the ASE module. The continuous gust analysis is now performed by the gust loads (GLOADS) module. Consequently, the GUSTID entry of the ASE bulk data card has been changed to now refer to an MLDSTAT bulk data card instead of the older CONGUST bulk data card but. The MLDSTAT bulk data card allows the ASE module to output the state-space matrices in the airframe states via an ASEOUT bulk data card. See the Remarks of ASEOUT for more details.
The frequency domain transfer function can now be calculated by the ASE module and can be output to MATLAB via the ASEOUT bulk data card.
A new bulk data card PLTSURF has been added to output a graphic plot file of the deflected control surface on the aerodynamic model.
The hinge line of an ASESURFZ bulk data card (to define a control surface) can now be defined via the z-axis of the CORD2R bulk data card. This is implemented to facilitate the user a simpler method to input the CORD2R card used to define the control surface hinge line. This option is activated by inputting a negative identification number of the referenced CORD2R card within the AESURFZ bulk data card.
The ZAERO FEM module has been extended to read in an ABAQUS output file that has been converted to an IDEAS neutral file format by specifying FORM=ABAQUS in the ‘ASSIGN FEM =’ executive control command. ABAQUS v6.5 and higher will have this output option using the toZAERO option.
The PLTTRIM bulk data card has been updated to export ABAQUS input formatted FORCE and MOMENT at structural grid points computed by the trim module.

Version 7.0 Enhancements

ZAERO now uses a license manager called Orion to handle both floating and node locked licenses. Earlier versions of ZAERO only supported node-locked licenses. A license server is now installed either locally (for node-locked installations) or on a server (for floating license installations) that manages the license usage. A license (or token) is issued to each computer that submits a ZAERO job. The total number of jobs that can be submitted concurrently is limited by the number of licenses (or tokens) purchased from ZONA.
A new module called ZTAW has been added to ZAERO to perform an AIC correction based on either the CFD solution or wind tunnel measurements. Four methods are incorporated into ZTAW; (1) the steady force correction matrix method, (2) unsteady force correction method using a successive kernel expansion procedure, (3) the steady downwash weighting method, and (4) the unsteady downwash weighting method using the successive kernel procedure. Four new bulk data cards are available for ZTAW; WT1AJJ, WT2AJJ, WT1FRC, and WTUCP. New test cases that demonstrate the ZTAW method have been added to the Application’s Manual (section 2.9).
Chapter 4.0 of the Theoretical Manual has been modified to present the theoretical formulation of ZTRAN, ZSAP, and ZTAW methods.
New test cases that demonstrate the ZTRAN and the ZTAW methods have been added to the Application Manual section 2.8 and section 2.9, respectively.

Version 6.4 Enhancements

A new transonic unsteady aerodynamic method called ZTRAN has been incorporated into ZAERO. Unlike the ZTAIC method that adopts a transonic equivalent strip theory methodology, ZTRAN is a true three-dimensional approach using an overset field panel method. ZTRAN requires volume cell modeling on the CAERO7/BODY7 macroelements that can be generated by three new bulk data cards, namely, CELLWNG, CELLBDY, and/or CELLBOX. In addition, ZTRAN requires the transonic steady flow solution at all volume cells that can be imported from a CFD Euler or Navier-Stokes steady solutions via a new bulk data card called INPCFD. The ZTRAN method generates a transonic unsteady AIC matrix that has the same form as that generated by ZONA6 and ZONA7. To activate the ZTRAN method, the user must set the METHOD entry of the MKAEROZ card to 3.
The entire gust module has been upgraded to incorporate three different methods for the discrete gust analysis. These three methods are, (a) frequency-domain approach, (b) state-space approach, and (c) hybrid approach. All three methods can deal with either open- or closed-loop systems. A new continuous gust analysis has been incorporated in the GLOADS module. A new bulk data card called CGUST is included to define the parameters of either Dryden’s or Von Karmen’s continuous gust spectrum.
The reduced frequency in the MKAEROZ bulk data card can now be negative. This negative sign triggers ZAERO to use more Gaussian integration points to solve the kernel integral. This feature can be used to partially circumvent problems with non-convergence at high-reduced frequencies whereby the number of chordwise boxes on the aerodynamic model is insufficient to yield a converged solution for these high-reduced frequencies. It should be noted that, more Gaussian integration points does not necessarily guarantee a converged aerodynamic solution. This can only be achieved by a refined enough aerodynamic model as discussed in Chapter 5.4 of the User's Manual (Issues Associated with High Reduced Frequencies).

Version 6.3 Enhancements

A mode acceleration method has been incorporated to compute the forces and section loads for the transient response analysis (MLOADS, ELOADS, and GLOADS disciplines). To activate the mode acceleration method, simply specify SOF=”YES” in the MLDPRNT bulk data card. For the pros and cons of the mode acceleration method versus the mode displacement method, please see the Remark 3 of the MLDPRNT bulk data card in the User’s Manual.
Three new bulk data cards, namely PCHFILE, CROSPSD, and EXTFILE have been added to output transient analysis results. The PCHFILE is used to read in an MSC.Nastran punch file that contains the modal values of element stress, strain, etc. The CROSPSD computes the cross-power spectrum density of particular parameters resulting from a continuous gust analysis. The EXTFILE stores the generalized coordinate results of the transient response analysis into an external file. Please see the User’s Manual for more details.
The computational speed of the transient response analysis (MLOADS, ELOADS, and GLOADS disciplines) has been greatly enhanced by only computing the transient results of the finite element grid points identified in the MLDPRNT bulk data card, whereas, older versions of ZAERO computed the transient results at all finite element grid points which could consume substantial computing time.

Version 6.2 Enhancements

A new Executive Control Command called GENGUST has been added to compute the gust aerodynamics. In earlier versions, the gust aerodynamics was always computed as a default. In version 6.2, the gust aerodynamics is computed only if the GENGUST Executive Control Command is specified. This update has the following impact on ZAERO: (a) Because the gust aerodynamics is no longer saved in the saved AIC external file if no GENGUST is specified, all AIC matrices created by previous versions of ZAERO cannot be retrieved by version 6.2. Therefore, one must re-run the AIC’s for version 6.2, and (b) If the gust discipline is involved in any subcases, the GENGUST Executive Control Command must be specified, otherwise a fatal error will occur.
A new discipline called Parametric Flutter Analysis has been developed that can be activated by the FLTPRAM Case Control Command that refers to a FLTPRAM bulk data card. This FLTPRAM bulk data card can perform a massive number of flutter analyses for various mass/stiffness of the structure and various control systems. FLTPRAM also outputs a summarized flutter result in table format in an external file that can be used to graphically display the massive flutter result. The FLTPRAM bulk data card is particularly useful for aircraft with various under wing store flutter analyses and parametric study of the stability of a closed-loop system with varying control system parameters.
Three new bulk data cards called CONM2, CONM2L, and CONM2* have been added to define a concentrated masses at grid points.

Version 6.1 Enhancements

The Finite Element Method (FEM) module has been updated to fix a bug that could occur when using CORD2x bulk data cards that reference CORD1x cards. The ability to process large field format for CORDxx and GRID bulk data cards has also been added.
- A new frequency domain ASE analysis for both open- and closed-loop systems without rational function approximation is included in the ASE module. To activate this option requires setting the RAAID entry in the ASE bulk data card to 0. This option will bypass the MINSTAT bulk data card that is used in the minimum state method and will perform a frequency domain ASE analysis without rational function approximation. This frequency domain analysis cannot generate a time domain state space equation. However, it eliminates any possible inaccuracies caused by the rational function approximation and thereby can serve as a “benchmark” solution to validate the time domain state space equation.
- The optimizer within the TRIM module for an over-determined trim system solution has been upgraded. The previous optimizer may converge to an inaccurate optimum solution, while the upgraded optimizer removes this problem. The output result of subcase 3 of case ha144d.inp (Test Case within the Trim analysis) has been upgraded based on the new optimizer results.
- The damping stability derivatives of a, b, p, q, and r can now be printed to the standard output file. This option is activated by setting the PRINT entry of the MKAEROZ bulk data card to 3. These damping stability derivatives are computed based on the smallest non-zero reduced frequency specified in the MKAEROZ bulk data card and are printed after the output of the generalized aerodynamic force matrix for this reduced frequency.
A bug has been fixed within the wing-body aerodynamics computation. This bug may occur when the ATTCHR or ATTCHT entries of the CAERO7 bulk data card is activated. These entries generate the vortex-carry-through (VCT) panels used to account for wing-body juncture aerodynamics. This bug will not occur in all cases. But in situations when it does occur, its effect could be to slightly change the flutter solution.

Back to top

Version 6.0 Enhancements

The ZTAIC (transonic unsteady aerodynamic method) now requires that the airfoil shape be input via the PAFOIL7 bulk data card. This enhances the robustness of the airfoil design scheme involved in the ZTAIC method in which the input airfoil shape is used as the initial guess in the airfoil design procedure to match the input steady pressure. Using the ZTAIC method without specifying the PAFOIL7 input will result in a fatal error.
A nonlinear flutter module for transient response of an aeroelastic system involving nonlinear structure, nonlinear control system, or large amplitude unsteady aerodynamics has been added in version 6.0. This nonlinear module is called the NLFLTR module that can be invoked by specifying a new case control command called [ NLFLTR = n ]. Two new bulk data cards are introduced for this method, namely, NLFLTR and NLSYSM. Two examples in using this NLFLTR module have been added to the Application’s Manual; (1) a three-degree-of-freedom airfoil with freeplay and (2) a strut-braced wing subjected to discrete gust, to demonstrate the input procedure for this new module.
A new flutter analysis bulk data card called FLTFAST has been added to allow for rapid g-method flutter analysis to be performed. This FLTFAST bulk data card employs a fast but less robust g-method algorithm whose computational speed is at least five times faster than the standard g-method employed by the FLUTTER bulk data card. Just like the FLUTTER bulk data card, this new FLTFAST bulk data card is referred to by the [ FLUTTER = n ] case control command. The flutter mode tracking and any flutter mode animation via the PLTFLUT bulk data card will not be performed for this method.
A new SPLINEM bulk data card has been introduced that allows for saving of the spline matrix. The saved spline matrix can then be retrieved in subsequent ZAERO runs in order to save the computational time required to generate the spline matrix. Note that this SPLINEM bulk data card will only work if both the aerodynamic and structural models are not altered between ZAERO runs. An example of its use would be if you only need to change the Mach number (on the MKAEROZ bulk data card).
The scheme to save the Aerodynamic Influence Coefficient (AIC) matrices via the MKAEROZ bulk data card has been modified in version 6.0. This provides a 70% reduction in computer time while retrieving the AIC matrices during a restart run. IMPORTANT: All previously saved AIC matrices prior to version 6.0 cannot be read by this new version. Thus, the user must re-generate these AIC’s before performing any restart runs.
To save time when reading the NASTRAN standard output file (*.f06 file), the user can now specify DISP=n in the NASTRAN Case Control deck where n refers to a SET Case Control Card that lists only those grids used by ZAERO; for example, grids referenced by the SPLINEi bulk data cards, grids referenced by the ASESNSR bulk data card, etc.
Three new bulk data cards called CONM2, CONM2L, and CONM2* have been added to define a concentrated masses at grid points.

Versions 5.2 & 5.3 Enhancements

A new unsteady aerodynamic method for sonic Mach number called ZSAP (ZONA Sonic Acceleration Potential) method has been developed and integrated in the UAIC module of ZAERO. To run ZSAP, in the MKAEROZ bulk data card, set the Mach number exactly to 1.0 and the METHOD entry to be 0.

This method allows for the aeroelastic solution at Mach 1.0, which cannot be obtained by the ZTAIC transonic method in the UAIC module. The runtime of the ZSAP method is substantially less than that of the ZTAIC method and is on the same order as the linear methods (ZONA6 and ZONA7).
An aeroheating analysis capability is incorporated in the UAIC module. To perform aeroheating analysis, in the MKAEROZ bulk data card, set the METHOD entry equal to –2 and activate the THERMO bulk data card (a new bulk data card). This aeroheating analysis generates temperature, heat flux, skin friction coefficients distributions as well as streamlines over the aerodynamic model.
A continuation line option is now available for the ‘ASSIGN FEM=’ and ‘ASSIGN MATRIX=’ executive control commands. The continuation line is determined by ending the first line with a comma (,).
The large field format for the GRID bulk data card (e.g., GRID*) in the NASTRAN file (i.e., the *.f06 file) is now readable by ZAERO.
Two new bulk data cards in the ASE module, called EXTINP and EXTOUT are introduced to allow for defining external input and output of the control system. Furthermore, the EXTINP bulk data card is also referred to by the MLDCOMD bulk data card for defining the pilot input command in the transient maneuver loads analysis.

Now the ZONA7U (hypersonic) unsteady aerodynamic method can handle blunt nose bodies in hypersonic flow. To activate this new hypersonic capability, the user must specify the nose radius in the SEGMESH bulk data card. This blunt nose capability circumvents the superinclined panel problem in supersonic/hypersonic flow and provides accurate hypersonic solutions in the nose region.

Section 5.0 of the Applications Manual has been changed. The older title was “How to Import the User Supplied Generalized Aerodynamic Forces for Flutter/ASE Analysis.” The new title is “How to Import the User Supplied Generalized Aerodynamic Matrices and Structural Matrices.” In this new section, a description on how to import the non-diagonal generalized mass and stiffness matrix is presented. Importing the generalized aerodynamic force matrices from a user’s own unsteady aerodynamic code(s) is also described.

Back to top

Version 5.1 Enhancements

The Permanent Database File ZAERO.INF has been changed to ZAERO.DBS to avoid potential attacks by computer viruses. To run version 5.1 and later versions, the user should ensure that this file is properly named in the ZAERO home directory (note: you can manually rename the file from ZAERO.INF to ZAERO.DBS).
A KLIST field entry has been added to the MINSTAT bulk data card that allows for the removal of unwanted reduced frequencies from the rational aerodynamic approximation.
The identification number of the CONMLIST and FLUTTF bulk data cards can now be a negative integer to “trigger” the program to re-compute the natural frequencies of the structure.
Two new bulk data cards called GRIDFRC and JETFRC have been added to define a control force at the structural grid points and a control force due to jet, respectively. GRIDFRC and JETFRC can be employed by the aeroservoelastic (ASE), static aeroelastic analysis (TRIM), and transient response analysis (MLOADS, GLOADS, ELOADS) as a control force.
An ejection loads module (called ELOADS) has been incorporated to compute the transient response due to store ejection for either an open- or closed-loop system. The new bulk data cards for the ELOADS analysis are: ELOADS and DFORCE. Running ELOADS requires an “ELOADS = xxx” case control command specified (a new case control command) in the case control section of the input file. This module is a new option to ZAERO. Please contact ZONA Technology, Inc. to order this option.
A discrete gust loads module (called GLOADS) has been incorporated to compute the transient response due to discrete gust for either an open- or closed-loop system. The new bulk data cards for the GLOADS analysis are: GLOADS and DGUST. Running GLOADS requires a “GLOADS = xxx” case control command specified (a new case control command) in the case control section of the input file. This module is a new option to ZAERO. Please contact ZONA Technology, Inc. to order this option.

Version 5.0 Enhancements

An “NE” option has been added to the “ASSIGN FEM =” executive control command to import the FEM solution generated by NE/NASTRAN (NE/NASTRAN is a product of Noran Engineering, Inc., 5182 Katella Ave Ste. 201, Los Alamitos CA 90720-2855, U.S.A., Tel. (562) 799-9911, www.NENastran.com).
A maneuver loads module (MLOADS) has been incorporated to compute the transient response of a structure for either open or closed-loop systems due to pilot input command(s). New bulk data cards for MLOADS are: MLDCOMD, MLDPRNT, MLDSTAT, MLDTIME, MLOADS, PLTTIME, and TABLED1. Running MLOADS requires that an “MLOADS = ” case control command be specified (a new case control command) in the case control section of the input file.
The units of the PZTMODE bulk data card input for a trim analysis has changed. In previous versions, the units of PZTMODE are in degrees. Thus, a factor of 3.14159/180. is applied to the G-set displacement of PZTMODE. In version 5.0, no such a factor is applied. Therefore, the aerodynamic forces generated by PZTMODE are directly proportional to the G-set displacement specified by the PZTMODE bulk data card. In the output file, the unit of PZTMODE is marked as “N/A.” This change has no effect on the ASE analysis.

Version 4.3A Enhancements

Hypersonic capability for an arbitrary body (BODY7) has been added in the new ZONA7U method. The new ZONA7U method can account for hypersonic effects for wing-body combinations whereas the prior versions only consider the hypersonic effects only for wing like components (i.e., CAERO7's).
A body wake bug that occurred with the CPBASE entry in the PBODY7 bulk data card has been fixed.
Added an ESA output option in the PLTCP, PLTTRIM, and PLTVG bulk data cards to produce the output compatible for the PEGASUS plotting software used by Boeing Commercial.
The required number of FEM modes from the modal coordinate solution in Trim module can be printed. As the structural deformation due to trim loads is of superposition of FEM modes, the user can determine the contribution of each mode to the static aeroelastic solution.
PLTTRIM bulk data card in the Trim Module now outputs the FORCE and MOMENT bulk data cards for NASTRAN, only at the structural grids connected to the Aerodynamic model through SPLINE. This is to minimize the resulting output file size.
In bulk data card TRMFNC for TYPE=FEM, the LABEL can be either LOADMOD or GRIDDISP. For the latter case, ISSET is an integer representing the ID of the structure grid point and IASSET is the component number of the displacement. This new option defines the trim function as the displacement at the structure grid.
In the PLTTRIM card, the field TYPE can be ELASTIC to output the deformed aerodynamic model indicating only the elastic deformation. Rigid body modes are excluded.

Version 4.3 Enhancements

An OUTPUT4 bulk data card has been added to output the required matrix in a format compatible with MSC.Nastran. The output is stored as a data file with a name specified by the user (please see the User's Manual bulk data card OUTPUT4 for a complete description).
The field ‘FORM’ in the PLTCP card has been updated to output the magnitude and phase angle (CP real and CP imaginary components) of the unsteady pressures for the reduced frequencies specified in the MKAEROZ bulk data card. This output option is now consistent with the FEMAP, I-DEAS, and PATRAN output formats.
Added an ANSYS plot file option for the PLTAERO, PLTCP, PLTMODE, PLTFLUT, and PLTTRIM bulk data cards. The ANSYS output is in the FEMAP neutral file format and requires the FEMAP neutral file to ANSYS translator built into the latest release of ANSYS. This addition to ANSYS can be obtained from either Phoenix Analysis & Design Technologies, Inc. (PADT): 1465 N Fiesta Blvd, Suite 107, Gilbert AZ 85233, Tel (480) 813-4884 / 1-800-293-PADT / Fax (480) 813-4807, www.padtinc.com or ZONA Technology at (480) 945-9988 / Fax (480) 945-6588, www.zonatech.com.
- A field option has been added in the PLTAERO, PLTCP, PLTMODE, PLTFLUT, and PLTTRIM bulk data cards to create neutral and result files compatible to PATRAN.
- An ESA formatted output option has been added to the PLTCP and PLTVG bulk data cards. 2D stripwise pressures and V-g plots are supported through this option. The ESA format provides compatibility with the PEGASUS plotting software of Boeing.