# Accession Number:

## AD0483258

# Title:

## SPECTRAL AND EXCEEDANCE PROBABILITY MODELS OF ATMOSPHERIC TURBULENCE FOR USE IN AIRCRAFT DESIGN AND OPERATION

# Descriptive Note:

## Final rept. Jun 1964-May 1965

# Corporate Author:

## CORNELL AERONAUTICAL LAB INC BUFFALO NY

# Personal Author(s):

# Report Date:

## 1965-11-01

# Pagination or Media Count:

## 94.0

# Abstract:

Atmospheric turbulence data in many forms, from many sources, have been combined in both spectral and exceedance probability models of the vertical component of atmospheric turbulence. These models will be useful in aircraft structural design procedures as well as in other analytical procedures involving aircraft operation. For the spectral probability model, a simple analytical form for the spectrum is chosen which fits well the available measured spectra. The parameters of the spectrum are related to physical and meteorological factors in tabular and graphical form, and probability distributions of the pertinent meteorological parameters have been obtained from climatological data. The resulting probability distributions of the spectral parameters have been computed. A normalized exceedance model is developed that represents the overall cumulative probability distribution of the vertical turbulence velocity for the special probability density function of the rms vertical gust velocity recommended in NACA TN 4332. The basic model involves one parameter, altitude, but may be modified, by using correction factors that are also developed, to account for varying terrain roughness, nature of the terrain, season, time of day and geographical location. These models of the vertical component of atmospheric turbulence represent what should be an improvement over previous models because of the significant amount of data which has become available in recent years.

# Descriptors:

- *MATHEMATICAL MODELS
- *ATMOSPHERE MODELS
- VELOCITY
- AIRCRAFT
- DISTRIBUTION
- PROBABILITY
- INTENSITY
- TURBULENCE
- ATMOSPHERIC MOTION
- TERRAIN
- SURFACE PROPERTIES
- MATHEMATICAL ANALYSIS
- OPERATION
- GUSTS
- STATISTICAL DISTRIBUTIONS
- METEOROLOGICAL PHENOMENA
- DIURNAL VARIATIONS
- CONVECTION(ATMOSPHERIC)
- PERIODIC VARIATIONS
- THUNDERSTORMS
- AIRCRAFT DESIGN

# Subject Categories:

- Aircraft
- Atmospheric Physics
- Statistics and Probability