Asymptotic approximations for modified Bessel functions

1980 ◽  
Vol 21 (1) ◽  
pp. 6-13 ◽  
Author(s):  
P. Kasperkovitz
Keyword(s):  
Bessel Functions ◽  
Asymptotic Approximations ◽  
Modified Bessel Functions

scholarly journals On the numerical computation of cylindrical conductor internal impedance for complex arguments of large magnitude

2017 ◽  
Vol 30 (1) ◽  
pp. 81-91 ◽  
Author(s):  
Slavko Vujevic ◽  
Dino Lovric
Keyword(s):  
Numerical Computation ◽  
Numerical Algorithm ◽  
Bessel Functions ◽  
Unit Length ◽  
Exact Formula ◽  
Asymptotic Approximations ◽  
Modified Bessel Functions ◽  
Large Magnitude ◽  
Internal Impedance ◽  
Cylindrical Conductors

In this paper a numerical algorithm for computation of per-unit-length internal impedance of cylindrical conductors under complex arguments of large magnitude is presented. The presented algorithm either numerically solves the scaled exact formula for internal impedance or employs asymptotic approximations of modified Bessel functions when applicable. The formulas presented can be used for computation of per-unit-length internal impedance of solid cylindrical conductors as well as tubular cylindrical conductors.

UNIFORM ASYMPTOTIC APPROXIMATIONS FOR THE WHITTAKER FUNCTIONS Mκ,iμ(z) AND Wκ,iμ(z)

2003 ◽  
Vol 01 (02) ◽  
pp. 199-212 ◽  
Author(s):  
T. M. DUNSTER
Keyword(s):  
Hypergeometric Functions ◽  
Turning Point ◽  
Bessel Functions ◽  
Asymptotic Approximations ◽  
Whittaker Functions ◽  
Modified Bessel Functions ◽  
Airy Functions ◽  
Double Pole ◽  
Confluent Hypergeometric Functions ◽  
Uniform Reduction

Uniform asymptotic approximations are obtained for the Whittaker's confluent hypergeometric functions Mκ, iμ(z) and Wκ, iμ(z), where κ, μ and z are real. Three cases are considered, and when taken together, result in approximations which are valid for κ → ∞ uniformly for 0 ≤ μ < ∞, 0 < z < ∞, and also for μ → ∞ uniformly for 0 ≤ κ < ∞, 0 < z < ∞. The results are obtained by an application of general asymptotic theories for differential equations either having a coalescing turning point and double pole with complex exponent, or a fixed simple turning point. The resulting approximations achieve a uniform reduction of free variables from three to two, and involve either modified Bessel functions or Airy functions. Explicit error bounds are available for all the approximations.

Asymptotic expansions and converging factors V. Lommel, Struve, modified Struve, Anger and Weber functions, and integrals of ordinary and modified Bessel functions

1959 ◽  
Vol 249 (1257) ◽  
pp. 284-292 ◽  
Keyword(s):  
Asymptotic Expansions ◽  
Bessel Functions ◽  
Modified Bessel Functions ◽  
Lommel Functions ◽  
Special Cases

A theory of Lommel functions is developed, based upon the methods described in the first four papers (I to IV) of this series for replacing the divergent parts of asymptotic expansions by easily calculable series involving one or other of the four ‘basic converging factors’ which were investigated and tabulated in I. This theory is then illustrated by application to the special cases of Struve, modified Struve, Anger and Weber functions, and integrals of ordinary and modified Bessel functions.

(p, q)-Extended Bessel and Modified Bessel Functions of the First Kind

2017 ◽  
Vol 72 (1-2) ◽  
pp. 617-632 ◽  
Author(s):  
Dragana Jankov Maširević ◽  
Rakesh K. Parmar ◽  
Tibor K. Pogány
Keyword(s):  
Bessel Functions ◽  
Modified Bessel Functions

Approximated Fundamental Frequency for Thin Circular Plates Clamped or Pinned at the Edge

2007 ◽  
Author(s):  
George Weiss
Keyword(s):  
Circular Plate ◽  
Fundamental Frequency ◽  
Bessel Functions ◽  
Unit Area ◽  
Continuous System ◽  
Modified Bessel Functions ◽  
Circular Plates ◽  
Numerical Parameter ◽  
Elliptical Plate ◽  
Distributed Load

Calculating the exact solution to the differential equations that describe the motion of a circular plate clamped or pinned at the edge, is laborious. The calculations include the Bessel functions and modified Bessel functions. In this paper, we present a brief method for calculating with approximation, the fundamental frequency of a circular plate clamped or pinned at the edge. We’ll use the Dunkerley’s estimate to determine the fundamental frequency of the plates. A plate is a continuous system and will assume it is loaded with a uniform distributed load, including the weight of the plate itself. Considering the mass per unit area of the plate, and substituting it in Dunkerley’s equation rearranged, we obtain a numerical parameter K02, related to the fundamental frequency of the plate, which has to be evaluated for each particular case. In this paper, have been evaluated the values of K02 for thin circular plates clamped or pinned at edge. An elliptical plate clamped at edge is also presented for several ratios of the semi–axes, one of which is identical with a circular plate.

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