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About CFD Online

CFD Online is an online center for Computational Fluid Dynamics. Services include several discussion forums, a jobs database, a free CFD reference in the form of a CFD-Wiki, a news and announcement forum, a books guide, an events calendar, and a comprehensive annotated link section with pointers to CFD resources around the world. CFD Online's goal is to offer high-quality web services to the CFD community. The site is independent and it is financed mainly by banner-ads.

Today CFD Online is the largest and most popular CFD site on the Internet. During a typical week the web site is visited by more than 81,000 people (unique IP addresses), downloading 570,000 web pages per week. In total there are more than 8,000 web sites around the world with links to CFD Online. In 2016 CFD Online celebrated 22 years of uninterrupted service to the CFD community! CFD Online continues to grow and strengthen its position as the world's leading CFD portal. CFD Online is top-listed by all major search engines and has received many awards over the years.


2016 was a very successful year for CFD Online. We had a fantastic growth in traffic and for the first year ever CFD Online on average delivered more than 2.5 million web-pages per month to our visitors! Both the number of read web pages and the number of unique visitors (IP addresses) reached new record levels. The number of read web-pages increased by 39% and the number of unique visitors increased by 13% compared to the previous year. This is the strongest growth in traffic that we have ever had. The bar chart above shows the 12-month trailing average of the number of web pages delivered from CFD Online per month over the previous 18 years.

Note that these statistics exclude access from robots and common search engines like Google, Bing and Yahoo. This is necessary in order to give a true representation of the traffic from real humans. Otherwise the quickly growing traffic from Google and other search engines robots would completely overshadow human visitors.

Visitor Demographics

Visitors to CFD Online come from typical CFD sites from all over the world. The pie chart below shows the traffic distribution across different top-level domains. Further details about where traffic is coming from can be found in the web server statistics report at or in the most recent web-server statistics.

In 2016 we saw an increased usage of the many hundreds of new top-level domains that are not tied to a certain location. Last year less domains were available and those available were not very popular. Another interesting trend is that China (.cn) is now almost gone from our traffic. We still have many users from China though, but they are hidden behind anonymous proxies. Traffic from Germany remains very strong and is more than twice as big as the second European country, United Kingdom. More and more companies are hiding behind anonymous numerical or network addresses and this makes it increasingly difficult to locate where traffic is coming from. On the browser side Chrome has completely taken over as the most popular browser with 50% of all traffic. On the OS side we see a slight reduction in Linux usage from 18% to 15%. Usage of mobile devices continues to increase and Android + iOS now accounts for almost 7% of our traffic, most likely due to an increased usage of our popular free forum apps.


The pie chart below shows the relative number of page-downloads for the different services at CFD Online. In total, the discussion forums are still the most popular section, with 46% of all the page-views. The CFD-Wiki has 33%, the Events calendar 7%, the CFD Jobs Database 8%, and the Links section 1% of all page-views.

The strong growth in traffic to the discussion forums, seen in previous years, has continued also in 2016. CFD Online remains the most popular meeting place on the net for free and independent discussions about CFD. Users seem to prefer the open forums at CFD Online over closed forums run by code vendors. The following services are currently available at CFD Online:

News and Announcement Service

The largest free online CFD news service. The news section has 4,500 unique visitors every month and more than 4,700 people are subscribed to the weekly email news-digest.

Discussion Forums

The most popular meeting place on the net for people interested in CFD. The forums have more than 600,000 archived messages in 150,000 threads from the previous 19 years.


CFD-Wiki is intended to eventually become the ultimate free CFD reference and text-book. The content is written collaboratively by thousands of users. CFD-Wiki contains more than 550 articles on various CFD related subjects. Many engineers and students use it as a valuable reference.

Links Section

The links section is very well known in the CFD world and continues to attract many return visitors year after year. It has been the largest collection of CFD links available on the net since it was introduced in 1994. In 2012 a major overhaul of the whole links section was done.

CFD Jobs Database

The CFD Jobs Database is the section that attracts most people. The CFD Jobs Database is visited by more than 1,400 job-seekers every day! It is a very good way to recruit CFD experts. The CFD Jobs Database has had about 200 open positions advertised throughout 2016.

CFD Books Guide

The Books Guide is intended to assist students and professionals in finding good CFD books. The guide includes more than 200 books. After the server upgrade we have had problems with incompatibilities with the new hosting system. We hope to solve this soon.

Events Calendar

This service is intended to help students and professionals to find CFD related conferences, courses and workshops. The calendar currently includes 52 upcoming CFD events and since the service was opened in 2002 more than 2,600 events have been advertised in it.

Tools Section

The tools section contains online tools useful for CFD engineers and students: Two calculators, a unit converter, a Y+ estimation tool and a tool to convert and estimate turbulent properties.

Feeds Section

The feeds section was launched in 2012; it contains aggregated feeds of CFD news-sources, blogs, vendors, jobs and journals. This service has become an important tool to help people stay up to date.


CFD Online is only responsible for the documents on this server, not for any of the external references. All opinions expressed are personal opinions.

Software and Hardware

In December 2016 the entire site was switched to SSL/https based encryption. This increases security and makes it impossible to eavesdrop on communication. This is especially important when using public networks. Our servers, installed in June 2015, are working very well. The site is hosted on a virtual server based on Centos KVM technology. The virtual server runs on a dedicated production server with a failover system to quickly switch over to a backup server that stands online ready to take over in case of hardware problems.

Powered by RedHat Powered by RedHat Powered by KVM Powered by Apache Powered by MariaDB, MySQL, PHP

Our production server has a Xeon E3-1270v3 CPU, 32GB ECC RAM, and two mirrored RAID1 enterprice SSD disks to ensure a quick and reliable delivery of pages. We have plenty of room to grow and increase our traffic in the future.


Please tell us what you think about this site. Contact information can be found on the contacts page. We appreciate any comments or suggestions. It is always nice to get some feedback and not only strange connections from someone.far.away.sirius_b
"I consider it the obligation of scientists and intellectuals to ensure that their ideas are made accessible and thus useful to society instead of being mere playthings for specialists."

- Bjarne Stroustrup, from "Design and Evolution of C++"