JVL Overview
Summary Description
JVL (Jet Vortex Lattice) is a program for analysis of arbitrary 3-D aircraft configurations with blown lift. It is an extension of AVL (http://web.mit.edu/drela/Public/web/avl/), which itself is extended Vortex-Lattice method which captures the effects of aircraft rotation rates and control deflections. The main new feature in JVL is the modeling of jet sheets for application to externally blown wings, as an extension of the jet-flap theory, which assumes a very thin jet sheet issuing from the trailing edge. In JVL the jet sheet has a finite thickness, and also extends ahead of the wing and is in contact with the surface. JVL accounts for the local load imparted on a surface by a contacting curving jet sheet, and on the forces of propulsors which create the jet sheet, both of which are important for correct moment predictions.
Extended Jet Vortex-Lattice Model
- Aerodynamic Components
- Lifting surfaces
- Slender bodies
- Configuration definition
- Keyword-driven geometry input file
- Defined sections with linear interpolation
- Section properties
- camberline is NACA xxxx, or from airfoil file
- control deflections
- parabolic profile drag polar, Re-scaling
- jet blowing parameters
- Scaling, translation, rotation of entire surface or body
- Duplication of entire surface or body
- Singularities
- Horseshoe vortices (surfaces)
- Source+doublet lines (bodies)
- Finite-core option
- Discretization
- Uniform
- Sine
- Cosine
- Blend
- Control deflections and variables
- Via normal-vector tilting
- Leading edge or trailing edge flaps
- Flaps independent of discretization
- Jet intensity variation
- General freestream description
- alpha,beta flow angles
- p,q,r aircraft rotation components
- Subsonic Prandtl-Glauert compressibility treatment
- Aerodynamic outputs
- Aerodynamic forces and moments, in body or stability axes
- Trefftz-plane induced drag analysis
- Force and moment derivatives w.r.t. angles, rotations, controls
- Jet and propulsor contributions included in all forces and moments
Trim Calculation
- Operating variables
- alpha,beta
- p,q,r
- control deflections
- Constraints
- direct constraints on variables
- indirect constraints via specified CL, moments
- Multiple trim run cases can be defined, saved, recalled
Mass Properties
- Optional mass definition file (for trim setup, eigenmode analysis)
- User-chosen units
- Itemized component location, mass, inertias
- Trim setup of constraints
- level or banked horizontal flight
- steady pitch rate (looping) flight
Eigenmode analysis
- Predicts flight stability characteristics
- Rigid-body, quasi-steady aero model
- Eigenvalue root progression with a parameter
- Display of eigenmode motion in real time
- Output of dynamic system matrices
Release Conditions
The most important conditions are:
- You may copy, modify and redistribute JVL or its modifications freely.
- Any such redistributions must be done under the terms of the GPL,
else the permission is withdrawn.
Announcements
Software
Latest Versions
- jvl2.20.tgz (1.07MB)
JVL 2.20 for Unix and Win32. Gzipped directory tar image.
All source code, User Guide, sample JVL inputs.
Requires Fortran, C compilers, windowing support.
Documents
Accessibility
Authors:
- Mark Drela, drela (AT) mit (DOT) edu
- Harold Youngren, guppy (AT) maine (DOT) rr (DOT) com
Page Revisions
2 May 2024
- Page created. JVL 2.20