elib
DLR-Header
DLR-Logo -> http://www.dlr.de
DLR Portal Home | Imprint | Privacy Policy | Contact | Deutsch
Fontsize: [-] Text [+]

Numerical Investigations of Rotating Liquids with the DLR THETA code

Munk, Johannes (2016) Numerical Investigations of Rotating Liquids with the DLR THETA code. Master's.

[img] PDF - Registered users only
11MB

Abstract

Spin-up from rest (Rossby number Ro=1) for a completely fluid-filled cylinder (R = 0.707m, H = 2m) has been analysed analytically and numerically. As grounds for the analytical analysis the Wedemeyer model [38] along with its weaknesses has been investigated. It was found that contradictions exist in literature how to implement a non-linear Ekman compatibility condition. The governing partial differential equation (PDE) describing the circumferential velocity over the radius and time has been solved numerically applying MATLAB’s pdepe solver. Numerical studies applying the DLR THETA solver have been conducted for two liquids, water (1bar, 300K) and liquid hydrogen (LH2; 1bar, 22.91K). Furthermore, it has been investigated whether THETA is capable of holding an initialized rotating solution stable (initialization, Ro=0). Generally, one can conclude that a second order upwind scheme (QUDS) is more precise than a central differencing scheme (CDS), that the errors become smaller for larger dynamic viscosities ν (water always shows smaller errors than LH2) and lower rotational velocities Ω. Overall, the THETA results on the structured grids show what the analytical analysis predicts and mirror the expected physical behavior for the transients and the steady state solution good and very good, respectively. It is not clear why the computations on unstructured grids do not mirror the expected physical behavior. DLR DLR – Numerical Investigations of Rotating Liquids with

Item URL in elib:https://elib.dlr.de/109342/
Document Type:Thesis (Master's)
Title:Numerical Investigations of Rotating Liquids with the DLR THETA code
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Munk, JohannestumUNSPECIFIED
Date:2016
Refereed publication:No
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Number of Pages:129
Status:Published
Keywords:rotating liquids, spin-up, Ekman compatibility condition, rigid-body motion, DLR TAU/THETA
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Transport
DLR - Research area:Raumfahrt
DLR - Program:R RP - Raumtransport
DLR - Research theme (Project):R - Raumfahrzeugsysteme - Anlagen u. Messtechnik
Location: Göttingen
Institutes and Institutions:Institute of Aerodynamics and Flow Technology > Spacecraft
Deposited By: Bachmann, Barbara
Deposited On:16 Dec 2016 12:27
Last Modified:16 Dec 2016 12:27

Repository Staff Only: item control page

Browse
Search
Help & Contact
Information
electronic library is running on EPrints 3.3.12
Copyright © 2008-2017 German Aerospace Center (DLR). All rights reserved.