A little bit more advanced flowchart than the simple flowchart example at: http://www.texample.net/tikz/examples/simple-flow-chart/
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{positioning}
\usetikzlibrary{shapes,arrows,arrows,positioning,fit}
\begin{document}
\begin{figure}
\tikzstyle{decision} = [diamond, draw, fill=blue!20,
text width=5.5em, text badly centered, inner sep=0pt]
\tikzstyle{block} = [rectangle, draw, fill=blue!20,
text width=10em, text centered, rounded corners, minimum height=2em]
\tikzstyle{line} = [draw, -latex']
\tikzstyle{cloud} = [draw, ellipse,fill=red!20,
minimum height=4em]
\tikzstyle{decisionn} = [diamond, draw, fill=red!20,
text width=4em, text badly centered, node distance=4cm, inner sep=0pt]
\tikzstyle{blockk} = [rectangle, draw, fill=blue!20,
text width=8em, text centered, rounded corners, minimum height=2em]
\tikzstyle{blockkk} = [rectangle, draw, fill=red!20,
text width=6em, text centered, rounded corners, minimum height=2em]
\begin{tikzpicture}[node distance = 2cm, auto]\label{ams1}
% Place nodes
\node [block] (init) {Mutual approach \& geometry of cam-roller};
\node [block, below of=init] (identify) {Slicing technique};
\node [block, below of=identify] (Mr) {Guess initial film thickness};
\node [blockk, below left=1.5cm and -0.4cm of Mr] (Pr) {Asperity load};
\node [blockk, below right=1.5cm and -1.1cm of Mr] (Hr) {Lubricant load};
\node [decisionn, below left=1.25cm and 1.25cm of Hr] (de) {Ls};
\node [blockkk, right of=de, node distance=5.0cm] (upe) {Update film thickness};
\node [blockk, below left=1.5cm and -0.8cm of de,node distance=2.5cm] (Fr) {Friction (ASP)};
\node [blockk, below right=1.5cm and 1.0cm of de,node distance=2.5cm] (Fre) {Pressure \& film thickness};
\node [block, below right=2cm and 0cm of Fr] (Tr) {Friction (total)};
\node [blockk, right of=init, node distance=7.5cm] (intt) {Bulk temperature};
\node [coordinate, below right =1cm and 1cm of Fre] (rightt) {}; %% Coordinate on right and middle
\node [coordinate, left =1cm and 0.5cm of intt] (leftt) {}; %% Coordin
\node [blockk, below of=intt] (Reo) {Rheology, shear rate, shear stress, friction(lub)};
\node [blockk, below of=Reo] (Temprt) {Temperature algorithm};
\node [blockk, below of=Temprt] (Fric) {Friction(lub) \& average temperature};
\node [decisionn, below of=Fric, node distance=3cm] (decide) {Conver-\\gence?};
\node [blockkk, right of=Fric, node distance=3.4cm] (update) {Update Temperature};
\node [blockk, below of=decide, node distance=2.5cm] (sto) {Friction (LUB)};
%% Coordinate on right and middle
\node [coordinate, below right =1cm and -0.5cm of de] (righttt) {};
%% Coordin
\node [coordinate, below left =1cm and -0.5cm of de] (lefttt) {};
%% Coordinate on middle
\node [coordinate, below of=Mr, node distance=1cm] (middle) {};
%% Coordinate on right and middle
\node [coordinate, below right =1cm and -0.5cm of Mr] (rightttt) {};
%% Coordin
\node [coordinate, below left =1cm and -0.5cm of Mr] (leftttt) {};
%% Coordinate on middle
\node [coordinate, below of=intt, node distance=0.8cm] (middlee) {};
% Draw edges
\path [line] (init) -- (identify);
\path [line] (identify) -- (Mr);
%\path [line] (Mr.south) -- (Pr.north);
%\path [line] (Mr.south) -- (Hr.north);
\path [line] (Hr.south) -- node {} (de.north);
\path [line] (Pr) |- node {} (de);
\path [line] (de) -- node {no} (upe);
\path [line] (upe) |- (middle);
%\path [line] (de.south) -- (Fr.north);
%\path [line] (de.south) -- (Fre.north);
\path [line] (Fr.south) |- (Tr);
\path [draw,->] (Fre.south) |-(rightt)-|(leftt)-- (intt);
\path [line] (intt) -- (Reo);
\path [line] (Reo) -- (Temprt);
\path [line] (Temprt) -- (Fric);
\path [line] (Fric) -- (decide);
\path [line] (decide) -| node [near start] {no} (update);
\path [line] (update) |- (middlee);
\path [line] (decide) -- node {yes}(sto);
\path [draw,->] (sto.south) |-(Tr.east);
\path [draw,->] (de.south) |-(righttt)-|(Fr);
\path [draw,->] (de.south) |-(lefttt)-|(Fre);
\path [draw,->] (Mr.south) |-(rightttt)-|(Pr);
\path [draw,->] (Mr.south) |-(leftttt)-|(Hr);
\end{tikzpicture}
\caption{Flow chart for numerical solution procedure}
\end{figure}
\end{document}