A simplified dynamic model of parachute inflation

Wolf, Dean

doi:10.2514/6.1973-450

Cited by 12 publications

(7 citation statements)

References 8 publications

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“…The heritage approaches of Apollo and the UD233 simulation are discussed, as well as the DCLDYN and DSS algorithms currently used by CPAS. Finally, an appeal is made for a common approach first proposed by Wolf 9 that better presents itself for the prediction of loads and the derivation of appropriate input parameters.…”

Section: Equations Of Motionmentioning

confidence: 99%

“…The value of K may be derived from test data or a desired potential flow solution as a function of the projected radius, R p . Notably, Wolf 9 and Macha 10 have criticized Shape/Distance methods for disregarding the criteria and assumptions required to ensure dynamic similarity.…”

Section: A Apollo Heritagementioning

confidence: 99%

“…A summary of the heritage test techniques that were researched and not selected for this recommendation can be found in the appendix. Ultimately, the simplified dynamic model proposed and refined by Wolf 9 and Macha 10 , respectively, was selected by the authors as the best method for determining the added mass contributions during parachute inflation events. Macha's proposal for deriving the added mass coefficients found in Equations (7) and (8) is a more fundamental approach than the other researched techniques.…”

Section: Measurement Test Techniquesmentioning

confidence: 99%

“…In 1973, Wolf 9 proposed an inflation model that uniquely included a radial momentum conservation equation for the parachute skirt. This addition allowed the prediction of skirt area, not by an assumed air mass flux or a relationship to drag area growth, but instead based solely on data resolvable from steady state wind tunnel data.…”

Section: E a Simplified Dynamic Modelmentioning

confidence: 99%

“…As R p increases, the approximating ellipsoid evolves from a prolate to an oblate configuration in order to fulfill the volume and R p constraints. It is notable that both Wolf 9 and Macha 10 have criticized potential flow solutions for their inapplicability to real fluids.…”

mentioning

confidence: 99%

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Proposed Framework for Determining Added Mass of Orion Drogue Parachutes

Fraire

Dearman

Morris³

2011

21st AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar

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The Crew Exploration Vehicle (CEV) Parachute Assembly System (CPAS) project is executing a program to qualify a parachute system for a next generation human spacecraft. Part of the qualification process involves predicting parachute riser tension during system descent with flight simulations. Human rating the CPAS hardware requires a high degree of confidence in the simulation models used to predict parachute loads. However, uncertainty exists in the heritage added mass models used for loads predictions due to a lack of supporting documentation and data. Even though CPAS anchors flight simulation loads predictions to flight tests, extrapolation of these models outside the test regime carries the risk of producing non-bounding loads. A set of equations based on empirically derived functions of skirt radius is recommended as the simplest and most viable method to test and derive an enhanced added mass model for an inflating parachute. This will increase confidence in the capability to predict parachute loads. The selected equations are based on those published in "A Simplified Dynamic Model of Parachute Inflation" by Dean Wolf. An Ames 80x120 wind tunnel test campaign is recommended to acquire the reefing line tension and canopy photogrammetric data needed to quantify the terms in the Wolf equations and reduce uncertainties in parachute loads predictions. Once the campaign is completed, the Wolf equations can be used to predict loads in a typical CPAS Drogue Flight test. Comprehensive descriptions of added mass test techniques from the Apollo Era to the current CPAS project are included for reference.

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Section: Equations Of Motionmentioning

confidence: 99%

Section: A Apollo Heritagementioning

confidence: 99%

Section: Measurement Test Techniquesmentioning

confidence: 99%

Section: E a Simplified Dynamic Modelmentioning

confidence: 99%

mentioning

confidence: 99%

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Proposed Framework for Determining Added Mass of Orion Drogue Parachutes

Fraire

Dearman

Morris³

2011

21st AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar

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Parachute design for payload on LSU02 VTOL aircraft

Herdiana¹,

Arifin²,

Yudha³

2023

International Conference on Mechanical Engineering for Emerging Technologies (Icomeet 2021)

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A momentum-based indicator for predicting the peak opening load of supersonic parachutes

Way

2018

2018 IEEE Aerospace Conference

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In this paper, a new empirical indicator for predicting the peak opening loads of supersonic parachutes is presented. The proposed indicator is proportional to twice the free-stream dynamic pressure and the projected area of the parachute, which is equivalent to estimating the opening load as a percentage of the free-stream momentum flux through the projected area at the moment of peak inflation. The form of this expression is motivated by a classical control volume analysis of the aerodynamic forces acting on a parachute during inflation, under the simplifying assumptions of quasi-static and one-dimensional flow. For parachute geometries and flight conditions typical of Mars Entry, Descent, and Landing systems, the largest contribution to the total drag is shown to be a momentum flux term that is associated with the entrainment of atmosphere within the inflating parachute volume. Using this new method, empirical constants are calculated from existing flight reconstruction data and are shown to have a smaller standard deviation than similar constants determined using the customary indicator form, which is based on the steady-state subsonic drag and proportional to the parachute reference area. These empirical constants are also compared to an analytic estimate, derived from the control volume analysis, and shown to have excellent agreement across a wide range of Mach numbers and dynamic pressures for several parachute geometries. While opening loads estimated using both methods produce similar results at low supersonic Mach numbers typical of past inflations, the proposed method predicts notably larger loads at higher Mach numbers, those above Mach 2.0, due to the omission of any Mach Efficiency Factor. Several current Mars EDL projects have adopted this new indicator.

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A simplified dynamic model of parachute inflation

Cited by 12 publications

References 8 publications

Proposed Framework for Determining Added Mass of Orion Drogue Parachutes

Proposed Framework for Determining Added Mass of Orion Drogue Parachutes

Parachute design for payload on LSU02 VTOL aircraft

A momentum-based indicator for predicting the peak opening load of supersonic parachutes

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