Search for dissertations about: "high Rayleigh number"

Showing result 1 - 5 of 25 swedish dissertations containing the words high Rayleigh number.

2. 1. Experimental investigation of premixed ammonia combustion at high Karlovitz number conditions

   Author : Qingshuang Fan; Förbränningsfysik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Turbulent premixed combustion; Ammonia flames; Laser diagnostics; Flame structure; High Karlovitz number; Turbulent burning velocity; Fysicumarkivet A:2021:Fan;

   Abstract : This thesis aims to acquire deep knowledge on turbulent premixed combustion at high Karlovitz (Ka) number conditions with the help of laser-based diagnostic measurements.Considering that ammonia (NH3), as a carbon-free energy carrier, is a promising candidate for replacing conventional fossil fuels in the future, all the investigations in this work were carried out on ammonia/air premixed flames. READ MORE

4. 2. Turbulence Measurements in a Natural Convection Boundary Layer and a Swirling Jet

   Author : Abolfazl Shiri; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; swirl; constant current bridge; high Rayleigh number; natural convection; Jet; cold-wire thermometry; vertical cylinder; laser Doppler anemometry; turbulent boundary layers;

   Abstract : Two sets of experimental measurement were carried out on an axisymmetric swirling jet flow and a natural convection boundary layer. In the first experiment, the far field of an incompressible swirling jet, discharged into a quiescent ambient has been studied using laser Doppler anemometry. READ MORE

5. 3. Channel Related Optimization of Wireless Communication Systems

   Author : Fredrik Tufvesson; Institutionen för elektro- och informationsteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; time division duplex; multicarrier; Radio communication; orthogonal frequency division multiplex; channel estimation; pilot symbol assisted modulation; sub-channel spacing; sub-channel bandwidth; interchannel interference; cyclic prefix; intersymbol interference; Rayleigh fading; precoding; pre-compensation;

   Abstract : This thesis deals with different optimization problems in the design of wireless communication systems. It is mainly directed to the design of systems based on multicarrier techniques and orthogonal frequency division multiplex, OFDM, but some of the problems apply to single carrier systems as well. READ MORE

6. 4. Coding, Decoding and Multiuser Detection for Wireless CommunicationsCoding, Decoding and Multiuser Detection for Wireless Communications

   Author : Pål Orten; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; direct-sequence code division multiple access DS-CDMA ; sequential decoding; Rayleigh fading; multirate DS-CDMA; optimum distance spectrum; rate matching; rate compatible punctured convolutional codes; multiuser detection; nested codes;

   Abstract : In the strive for making the Universal Mobile Telecommunication System(UMTS) a reality, concepts and techniques are to be developed which canprovide both high system capacity and sufficient quality for the increasingnumber of mobile users. To obtain these objectives, powerful and flexibleerror control coding is needed, as well as efficient means for many usersto share the same commmication medium. READ MORE

7. 5. Short-Packet Communications: Fundamental Performance and Key Enablers

   Author : Johan Östman; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rayleigh fading; Block-fading channels; Rician fading; variable-length stop-feedback; short-packet channel codes.; ultra-reliable low-latency;

   Abstract : The paradigm shift from 4G to 5G communications, predicted to enable new use cases such as ultra-reliable low-latency communications (URLLC), will enforce a radical change in the design of communication systems. Unlike in 4G systems, where the main objective is to have a large transmission rate, in URLLC, as implied by its name, the objective is to enable transmissions with low latency and, simultaneously, very high reliability. READ MORE